Extending PR #23

Extending PR #23 and basically just rewriting the js for the datetime partial to support nil and to not be ugly as hell.
I added this bit of text to keep it clear what is required. Basically if you set a date, i just use the current time in UTC until you set a time. If you never set a time, that time is saved in your model. This essentially means that *only* the date is required, and the time portion is optional. If you set the date field to null this *should* set it to nil in the DB for the model.