DatesRole: Adding regex and failing tests for relative day parsig
DatesRole: Adding rough implementation for relative times
DatesRole: Minor tidyup
DatesRole: better protect against undef datestrings.
DatesRole: fix and expand relative dates.

- Add grouping to regex for proper |ing.
- Add 'year' to relative dates.  (See Chinese zodiac)
- Add more tests.
Merge remote-tracking branch 'origin/master' into mintsoft/relative_dates

Conflicts:
	lib/DDG/GoodieRole/Dates.pm
ChineseZodiac: update as example of working with relative dates.
DatesRole: minor cleanup
DatesRole: definededness not truthiness for parsing.

I don't know that we'd ever need to actually support year 0 or similar,
but there may come a day where we support epochs or something and it
might make sense.
DatesRole: add "this" week|month|year.

At this point,all of them are essentially aliases for "today", but the
logic is kept separate in case we want to move them to start of period
or similar.

Minor update on Chinese Zodiac to demonstrate it working through the
role instead of local triggering.
Chinese Zodiac: Adding support for plural vague terms
DatesRole: Renaming misleading regex
DatesRole: Clarifying terrible comment
DatesRole: Tidying up
DatesRole: Adding regex and failing tests for new proseque formats
DatesRole: Expanding test coverage and first (probably broken) implementation
DatesRole: refactoring into utility function
DatesRole: Restoring failing tests
DatesRole: Removing prototype from util sub
DatesRole: Commenting out tests that fail; leaving in "in a <unit>" as these pass?!