Light cleanup
No longer forces collection id's to be numeric.
Allow API requests to use content negotiation with the Accept header
Merge pull request #1081 from danielstjules/453f33dc1616e6f8d7c33aef7ce13d76e581295b

Quick cleanup and small fix for the API
Closes (PR) #726 : Error checking to the add section modal

 - add padding-bottom to the modal
 - add error checking to the modal
 - add remote requests to do not refresh the webpage
 - change location of select from _student_form to a partial
 - add rjs files to interact with the modal and the select sections
Merge pull request #1085 from GhiGt/issue-726

Closes #721 : Error checking to the add section modal.