Fixes issue 1069
Light cleanup
No longer forces collection id's to be numeric.
Allow API requests to use content negotiation with the Accept header
Addition to issue-415: removal of h in files
Merge pull request #1083 from danielstjules/issue-415

Issue-415: no longer need to use h to sanitize strings.
Merge pull request #1070 from mike-stewart/issue-1069

Issue 1069 - removes raw HTML from grade entry date column.
Merge pull request #1081 from danielstjules/453f33dc1616e6f8d7c33aef7ce13d76e581295b

Quick cleanup and small fix for the API
Merge branch 'master' of github.com:benjaminvialle/Markus into machinist2