Adapt @lpsmith's time parsers to Text and use in queries

Haskell's `read' UTCTime parser is pretty slow so start switching to a
more optimized time parser.

Adapts Leon P Smith's time parser to Data.Text.

Further commits will adapt for SQLite date/time format.
Adapt UTC time parsing for sqlite time strings

Allow UTC time strings of format:

YYYY-MM-DD HH:MM
YYYY-MM-DD HH:MM:SS
YYYY-MM-DD HH:MM:SS.SSS
YYYY-MM-DDTHH:MM
YYYY-MM-DDTHH:MM:SS
YYYY-MM-DDTHH:MM:SS.SSS
Add tests for new UTC time parser
Delete unused code
Use explicit parsers & builders for UTCTime and Day

- Make Day use the Database.SQLite.Simple.Time module in FromField
- Use Blaze builders for converting UTCTime & Day types to strings

Conveniently this also gets rid of the old-locale dependency in the
cabal file.
Add tests for parsing & building UTCTime and Day strings

Includes timezone offset tests which we didn't have before.