#969586 Completely refactor the form processing so previews work in overlay. Did a bunch of cleanup in the process, other things may have broken, this will need some shaking out.

#935076 Add tests, including one provided by tristanoneil, plus a few fixes uncovered by the tests. More tests coming, this is a start.

#929494, Got an ISO date with select widget working correctly with proper timezone conversions after implementing new FAPI workflow. Now need to get other field types working and add tests.

More clean up of formatters and formatter settings, more re-organization to make the code easier to maintain.

Re-organize all the field hooks into a single file and add the formatter settings form and summary. This will probably see more changes, this is a first pass.

Rework date repeat to use custom multiple values handling, we can't have multiple repeating date elements or everything breaks.

Add  to when altering field values, probably still missing some of these, more work on cleaning up new hook_field functions.

Remove more date format code that is now in core, change name of views field handler to new name, de-opify hook_field using new field parameters.