Respond to the remainder of sheel's feedback for reminders form UI

- add case property, subcase property, and form select2 dropdowns to fields
- renaming of some labels
- move help bubble
- whitespace cleanup
- timepicker for fire_time

![screen shot 2013-10-17 at 1 35 50 pm](https://f.cloud.github.com/assets/716573/1354324/a347dc06-3752-11e3-8cc3-0ca021203fdd.png)
![screen shot 2013-10-17 at 1 36 08 pm](https://f.cloud.github.com/assets/716573/1354323/a347a664-3752-11e3-81ef-31fbf3a27c93.png)