[META] Port all changes in 2.x to 3.x

7.x-3.x supports version 3 of the AWS SDK, but it has fallen behind 7.x-2.x.
The list below is the commit log for 7.x-2.x in descending date order. New commits go to the top.

• commit 48444d4625289bcead780454d42033c0f8e9284e
  Author: Rhane Colwell
  Date: Fri Jan 4 13:53:56 2019 -0500

  Issue #3016824 by nrackleff: Notice: Undefined index: s3fs_use_versioning
  Done: 163133266df1d9fc092da3722459f91938fbec9b

• commit 015f7a69fdad5a7f1247abf86d64294b7a3411b3
  Author: ron_s
  Date: Mon Sep 17 10:29:23 2018 -0700

  Issue #2981730 by ron_s: Copy system images to S3 when rendering direct paths to CSS/JS files
  Done: a73c058de90e6611b6ed4b5bfa0375cefcb675f6

• commit b7bf6db2f096510c19bfc255b3c86a7ef9f66b62
  Author: ron_s
  Date: Thu Sep 13 14:52:46 2018 -0700

  Issue #2969063 by ron_s: Allow domain name to map directly to root path
  Done: a434d69d564bce83a6711010ca20f5eae02caf0c

• commit 68fc0a799a7b98cba7c1920a251b51b9e46c6e63
  Author: Robert Rollins
  Date: Mon Sep 10 13:06:51 2018 -0700

  Issue #2998618: Reverted the AWS Secret Key field back to a textfield.
  Done: 0a9f9e62208296a112f2df7b43d29e77f890be73

• commit 930aec3d487056a63457fe1214c1a98ac2e5e6bd
  Author: eddie_c
  Date: Thu Aug 30 10:12:35 2018 -0700

  Issue #2996206 by eddie_c: each() deprecated in PHP 7.2 : Port patch from D8 to D7
  Done: 8ceb087bcd8a86cb64195ad108ad0198d3d51c72

• commit f0009f6aab5d24f8aee12169b716cd35f89a543a
  Author: eddie_c
  Date: Tue Jul 24 10:24:48 2018 -0700

  Issue #2900237 by eddie_c: PDOException: SQLSTATE[22001]: String data, right truncated
  Done: 571b305f385277041d093191f8f8af359763b602

• commit 5730b41a081801f4f216d27c8a827f4c12ab39e6
  Author: Robert Rollins
  Date: Thu Jul 5 14:12:11 2018 -0700

  Issue #2983481: Updated the list of available S3 Regions in the settings.
  Done: 506322eca452e21ab836a8a7785f0d85bcd0c02e

• commit 5531b4d49b6158ddb581f2b178e885b906699aa6
  Author: lambic
  Date: Tue Jun 12 10:20:34 2018 -0700

  Issue #2979162 by lambic: Add Canada to region list
  Done: 506322eca452e21ab836a8a7785f0d85bcd0c02e

• commit be127357a217c7c32584726b6d03e697800ba184
  Author: Robert Rollins
  Date: Mon Jun 11 11:37:21 2018 -0700

  Issue #2978480: Switched to drupal_basename() because PHP's basename() is broken on international filenames.
  Done: de58d0e5af27557e660e6785d4bc2d30414a7126

• commit 9d9fe33e60a09f9b40b01381c61d83949db4cb8f
  Author: ron_s
  Date: Mon May 21 10:28:37 2018 -0700

  Issue #2974070 by ron_s: Option to block access to S3 URLs if using a domain name
  Done: ce05fa4816fdbf87bea6ef0de7e33867f2d5200c

• commit 02ab4d191ffb297d8b7117747670ae333aaae934
  Author: ckitchens
  Date: Fri Apr 13 10:05:06 2018 -0700

  Issue #2958566 by ckitchens, coredumperror: Allow S3 Versioning as a Configurable Option
  Done: 163133266df1d9fc092da3722459f91938fbec9b

• commit a35df0a9c0ca6a6b42f6ca9463e4cefdfc62f274
  Author: ckitchens
  Date: Thu Apr 5 10:20:23 2018 -0700

  Issue #2958566 by ckitchens: Allow S3 Versioning as a Configurable Option
  Done: 163133266df1d9fc092da3722459f91938fbec9b

• commit 0eb12bc9d2771d11ca0ae356daa940cce41f16cd
  Author: Robert Rollins
  Date: Thu Apr 5 10:17:57 2018 -0700

  Various minor fixes that I've forgotten to to commit over the last while.
  Done: 0a9f9e62208296a112f2df7b43d29e77f890be73

• commit 714390a8ec7cfa2b58a83267a223e9a98ff94b01
  Author: ckitchens
  Date: Wed Apr 4 10:59:50 2018 -0700

  Issue #2957905 by ckitchens: Conditional Authorization for a Multi-Site / Single S3 Bucket Environment
  Done: 094a41dde417899b90b8a834bb055045a11a648c

• commit b3ce9ff65523f3623885d6a30463ab47b80d5ea0
  Author: Robert Rollins
  Date: Wed Nov 8 15:41:05 2017 -0800

  Issue #2632082: Bugfix for VersionId=='null'.
  Done: b3ce9ff65523f3623885d6a30463ab47b80d5ea0

• commit 51538a4267cfca727d5938905e996990f8f45449
  Author: Robert Rollins
  Date: Mon Aug 21 15:36:28 2017 -0700

  Fixed a lingering problem with the bad update hook from v2.9.
  Port: #3025452: Replace/remove the old s3fs_use_instance_profile var →

• commit c8cdd4bcd8b4e28df7aee9d357075b256d55db20
  Author: Robert Rollins
  Date: Fri Jul 14 11:52:43 2017 -0700

  Documentation update for API.
  Needs to be ported

• commit 00953a9c5c8c8bc9556b73ed002533a30c21b50b
  Author: marklaramee
  Date: Mon Jun 26 10:35:22 2017 -0700

  Issue #2886878 by Lams: "Refresh file metadata cache" fails in MySql 5.7.5+
  Port: #3180125: [7.x-3.x] Add support for very large object counts →

• commit 93306303b383c6afba2b8fc081dffc9609dbdaca
  Author: Robert Rollins
  Date: Thu Jun 8 10:59:24 2017 -0700

  Issue #2884388: Fixed broken stream_stat() method in S3fsStreamWrapper.
  Done: S3fsStreamWrapper no longer overrides stream_stat()

• commit 940ca805b09d5ef1a2779c8a61e7e48480a6009f
  Author: Robert Rollins
  Date: Fri Mar 10 14:17:46 2017 -0800

  Fixed a serious bug in the previous update hook.
  Port: #3025452: Replace/remove the old s3fs_use_instance_profile var →

• commit 93e82994d42a96c85f361ed410eaf60f995e6e37
  Author: Robert Rollins
  Date: Thu Mar 9 17:00:26 2017 -0800

  Replaced/removed the old s3fs_use_instance_profile var.

  Now, only the s3fs_awssdk2_use_instance_profile and awssdk2_use_instance_profile
  vars are used. If awssdk2_use_instance_profile is written into settings.php,
  it will override the s3fs_awssdk2_use_instance_profile variable.

  BACKWARD INCOMPATIBILITY NOTE: Anyone that hard-coded s3fs_use_instance_profile
  into their settings.php will need to change that line to use
  awssdk2_use_instance_profile instead.
  Port: #3025452: Replace/remove the old s3fs_use_instance_profile var →

• commit 63fae36098e72ec79e9228f4bdb4f5c6fd272440
  Author: Robert Rollins
  Date: Tue Mar 7 10:57:03 2017 -0800

  Issue #2858314: Corrected rmdir()'s improper SQL queries.
  Done: b1fbf385a79a16b0041c6381a63e4aa630ca4faf

• commit 08e6bc0630d3ce7b6dac65712b3c3dccaca78a29
  Author: Robert Rollins
  Date: Tue Mar 7 10:56:17 2017 -0800

  Removed pointless read caching of s3fs_file table.
  Done: cb445bb8faeadd306df46f3fd4c048c2a37ece04

• commit 50b379ab13ef6accb0dc66ae2f867258612e19e2
  Author: Robert Rollins
  Date: Tue Mar 7 10:55:46 2017 -0800

  Minor cleanup.
  Needs to be ported: only the added blank line before return $schema; is left.

• commit a9ca00b4c9949acdffe0bc7720ac42380a3f45a0
  Author: jansete
  Date: Sat Feb 18 19:21:01 2017 +0100

  Issue #2821971 by prince_zyxware, jansete: Fix coding standard - spacing issues
  Done: f1a7d4c59f031bf3de4e1105dec3320bdbfa1d33

• commit 6a730d09db34ee42cbea75f0ca13441a1bdd9837
  Author: jansete
  Date: Sat Feb 18 12:09:08 2017 +0100

  Issue #2853778 by jansete: Config form does not display region "EU - London (eu-west-2)"
  Done: 40b612307308dc06a6166589e8ce7ce7f59ae207

• commit 376889dd1f55ddbd796dadedf0e008ba3091ef93
  Author: Robert Rollins
  Date: Fri Feb 17 15:56:13 2017 -0800

  Added read/write permission checking to the default cache location.
  Needs to be ported

• commit 326e9813a1d1acaaff0f971c20b5b0742a20808d
  Author: Robert Rollins
  Date: Fri Feb 17 14:10:46 2017 -0800

  Caching of instance profile cedentials now actually works. Caviat: you now have to actually configure it properly.
  Needs to be ported

• commit 5a4cb4f4bb4ac60a70539c3fc4dae4e10c51e8c0
  Author: git
  Date: Mon Feb 6 12:33:32 2017 -0800

  Issue #2849510 by zaphoyd: Add support for Ohio/us-east-2 region
  Done: 39f1d35a1509a0e8398836bd384775cac360f571

• commit 2d260e2d6b1d665b95d64cb2c9ffeefcc148356e
  Author: Robert Rollins
  Date: Tue Jan 17 11:15:40 2017 -0800

  Issue #2630466 by mshade: documented nginx configuration throws 502 gateway error
  Done: b8939f09a790342591d3c7229056e290e15f963f

• commit 58998e325c4ef9ec91aa940927a1e74b9469c39d
  Author: Robert Rollins
  Date: Tue Jan 17 11:10:11 2017 -0800

  Issue #2843639: Clarified the "Don't rewrite CSS/JS file paths" setting's description.
  Done: b04986594bab10f928739111b35d366740e25c66

• commit e39f82fb8fc45fa1f71d74306f98026fbbaf779f
  Author: fluxsauce
  Date: Mon Jan 9 12:08:55 2017 -0800

  Issue #2464031 by FluxSauce, catbear: Add support for very large object counts
  Port: #3180125: [7.x-3.x] Add support for very large object counts →

• commit 0f0eea058da1a169d8d590884c6d9ceedba14222
  Author: Robert Rollins
  Date: Mon Jan 9 12:03:47 2017 -0800

  Issue #2826372: The new stream_metadata() API is now implemented.
  Done: S3fsStreamWrapper extends StreamWrapper so inherits the added method

• commit 30897b9a312ff83edc0e5ec98c0447606cd8c36c
  Author: shashwatpurav
  Date: Fri Dec 9 10:53:56 2016 -0800

  Issue #2833981 by Shashwat Purav: Remove extra single quote from README.txt
  Done: 4fd703d946f621e53565bcb754d98e603f308683

• commit 627427adb6a9dfaf57df3735a0102f215d1b1eef
  Author: shashwatpurav
  Date: Fri Dec 9 10:49:17 2016 -0800

  Issue #2833958 by Shashwat Purav: Add Asia Pacific (Mumbai) Region
  Done: a41611cd4a745f1f22848e8fc3645aaad66e08aa

• commit abf08b5ea9e95f18454110c3b271180c00543361
  Author: Robert Rollins
  Date: Tue Nov 8 10:37:43 2016 -0800

  Issue #2825806: Wrong bucket policy example in README
  Done: dd460b821c3cdfdc04290e92e1ac16c0e2c82ccf

• commit 39a74cf58b142f1cd1e00155d3080ede664e41eb
  Author: Robert Rollins
  Date: Tue Sep 20 10:43:55 2016 -0700

  Issue #2803121: Added support for the Seoul region.
  This commit is common to both branches. After this they diverge. Everything in 7.x-3.x is in 7.x-2.x except 5e6a4912df6d9cb90119d44011752e62a2686be7