Fix formats bug in form.TimeField

* when submitting a form that includes a TimeField:
  AttributeError: 'TimeField' object has no attribute 'formats'
* when populating a value into a TimeField:
  TypeError: strftime() argument 1 must be string or read-only buffer, not tuple
Merge pull request #99 from dbluestein/form-time-formats

Fix formats bug in form.TimeField