Make API call for sub button - ref #15
Added saving logic & populating creator - ref #15

saving logic for mustFollow/mustSub
Run follow/sub API calls, fixes #15

This also makes it so a poll creator can only create a sub-only OR a
follower-only poll, but not both. If you have a sub button, you will
only be able to create a sub-only poll.
Merge dev into issue-23
Fixed formatting - Fixes #23