Merge pull request #22 from RajShah94/develop

Set Exam Mode
Revert uncommenting of course attribute setting
included PUT pemission for the admins to set examMode
fixed wrongly swapped selectAll and selectNone buttons.
fixed usrstatus url to not have an extra slash.
changed color of examMode and added a toggle shield button
Added methods to toggle shield status, set exam mode on user status and select and unselect user statuses.