Add initial simpletest

Module has no test. There should be. Some things I can think of:

• Does not interfere with alt and title.
• Views support.
• • Image field with caption
  • Image field without caption.
  • Views support with tokens.
  • Image caption field test.
• Image show up as expect based on default template.
• Permission
• • Has permission to edit caption (currently not implemented)
  • Cannot edit the caption if they do not have access to the current text format.
  • Cannot edit the caption and no errors on the page thrown.

There is probably a lot more, but this is what I came up with on first brainstorm.