Remove redundant pattern

It's not being used anywhere.
Improve formatting of read validation.
Tidy up parsing a query from request args
Create timeutils

Move now and parse_time_string into it and remove a bit of duplication.

Also rename parse_time_string to parse_time_as_utc.
Move utc function to timeutils.
Merge pull request #91 from alphagov/minor-cleanup

Variety of minor cleanups