Improved equalTime failure message

Added expected and actual values to the assert() call so that the correct values show up in the output from a failure if diff is shown.

Before change:
AssertionError: expected Thu Jul 31 2014 00:00:00 GMT-0400 (EDT) to equal Wed Jul 30 2014 23:59:59 GMT-0400 (EDT)
Expected :undefined
Actual   :{}

After change:
AssertionError: expected Thu Jul 31 2014 00:00:00 GMT-0400 (EDT) to equal Wed Jul 30 2014 23:59:59 GMT-0400 (EDT)
Expected :"Wed Jul 30 2014 23:59:59 GMT-0400 (EDT)"
Actual   :"Thu Jul 31 2014 00:00:00 GMT-0400 (EDT)"
Merge pull request #15 from TwineHealth/master

Improved equalTime failure message