Don't crash when student_rsvp_limit is set to empty string
Restore select2-ness of chapter leader dropdown

select2ified dropdowns will now get select2 javascript applied
to them when you add a .select2-dropdown class to the <select>.

Previously, they all just used their own magic ids.
Add RSVP form previews to organizer console

- If the person looking at the organizer console hasn't RSVP'd (so, like, an admin), submitting this form will make a new RSVP
- Organizers already have an RSVP, so they'll just see a "user has been taken" error
Reorganize new event page

- Futz with margins and font sizes a whole lot
- Add dark grey btn-info
- Add helper text galore
- Reword +1 form text to not say RailsBridge specifically
Merge branch 'master' into lillie-organizer-rsvp-form-previews
Consolidate volunteer and student rsvp preview routes

Remove 'submit' button from RSVP when previewing
remove silver, insert pink
remove btn-silver, insert btn-pink
remove silver, insert pink
remove silver, insert pink
Merge branch 'master' of https://github.com/kmolo/bridge_troll