Made some fixes to find and test the right entities when checking whether to use default values. More work is needed.

Issue #1422600, Make sure end date cannot cause validation errors when show end date checkbox is not checked.

Issue #1417872, Remove code to compute missing date parts from empty values now that the new validation prevents that from working.

Issue #1417872, Make sure empty year field is validated in the same way other date parts are validated.

Make sure only new entities pick up default values, to avoid resetting an empty value to the current date.

Issue #1017216 by tim.plunkett, arlinsandbulte: Added custom date format without time shows 'all day'.

Clean up the language for the new option to cache date values, and note that it could cause performance issues.

Issue #1359464, Make sure that default values on hidden elements have the same construct as loaded values to avoid errors.

Issue #1399744 by tim.plunkett, Rework the way filter groups are used to be sure the Date filter group does not clobber the Views filter group.

Issue #1411862, Move the date_views_fields() function into date_view.module to be sure it is always available.

Issue #1380350, Rework SQL query handling to pass in a comparison date for computing offsets to better handle dates affected by DST adjustments.

Issue #1359464, Temporary fix for broken handling of repeating dates on users with a TODO to figure out where it's coming from.

Issue #1404494 by byrond, Make sure hidden formatters don't get switched to date_default in update hook.

Issue #1408430, Views pagination with exposed, unset, filters, results in invalid default values. Treat them as empty input.