CMGR-2326 - set default start and end time

![Screen Shot 2013-03-21 at 10 25 21 AM](https://f.cloud.github.com/assets/1612134/287759/97ac11f2-925f-11e2-9728-83c46f7c6288.png)
What it currently looks like on load. It appears that it is not setting the default date implicitly behind the scenes. Trying to submit this form as is will throw two ```can't be blank and is not a valid datetime``` error's