for the reminders form, return message data in the same format that it came in
make sure that initial data is populated with a blank event otheriwse the reminder ui will be like 'what to dooo???'
populate time_window_length with an empty string instead of null on load of reminders ui
add is_immediate to the events asJSON in reminders form
since the value for callback intervals in reminders is stored as a list but edited as a string, flatten it here
reminders form shouldn't fail hard if start_offset is None
simplify phrase in reminder schedule form
Merge pull request #1440 from dimagi/reminders-ui-fixes

Reminders Form UI Fixes