#970614 by Mark Trapp Fix month abbr functions broken when switching from date_t() to new translate context system.

Trying to figure out how to get the list of date fields back into the date argument and filter. Something must have changed.

#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.

With new formatter settings we can simplify date formats. Make the format type a setting instead of having different formatters for each type. We can also add settings for the interval formatter later.

Finally found source of Missing join error message, don't add relationship if the the date is in the base table.

#518816 by dww, avoid 'date_format() expects parameter 1 to be DateTime' errors by checking for date class.