brief edits to classes intro
changed HTML to allow for mass grader
made mass-grade work
added form-control style
week10 with Thursday stuff
Merge pull request #56 from aerenchyma/classesch-edits

brief edits to classes intro
Merge branch 'mass_grader' of https://github.com/nickdotreid/runestone into nickdotreid-mass_grader
Merge branch 'pip' of github.com:presnick/runestone into pip
rearranged index.html page