Provide migrate support to upgrade from Date module on D7

Using the patch in #38 the "limit" end date of a recurrence is being specified with time in the string, and therefore not showing up in the UI – where only a date is allowed.

It looks, from smart date data that's been input manually (non-migrated), like the rule DB column does include HHMMSS ('\THis') in the UNTIL string but the limit column does not.

i.e.

Should be:
rule: RRULE:FREQ=DAILY;INTERVAL=1;UNTIL=2017-01-08T235900
limit: UNTIL=2017-01-08

But actually is migrated as:
rule: RRULE:FREQ=DAILY;INTERVAL=1;UNTIL=2017-01-08T235900
limit: UNTIL=2017-01-08T235900

Here's an update of the patch in #38.

Looks like @nightlife2008 had this issue too, with a similar solution in #32.

Missed the one that matters most. Fix and simplification.

One more try. Sorry for the spam.

There's another issue in ParseDates with the break; after generating new repeat values. It breaks out of the loop completely, meaning that additional values don't get processed at all.

This for me resulted in a bunch of " [warning] A non-numeric value encountered ParseDates.php:341" errors.

Updated patch to fix this.

Can anyone share an updated YAML to migrate a CT using this patch ?
Thank you very much.