Fixes issue with users/login => users_controller#show
Fixes subtasks count for teachers
Scopes users subtasks to the current projectGroup

Fixes #96. I think this should fix all the issues revolving around not having a student's subtasks scope to the current project group they're located at, but I can't be entirely sure. How I wish I had written more tests!
Only add the 'last-progress-bar' class when full

Fixes #51
Forgot to add a ';'. Doh
Added "[DISPUTED]" to disputed tasks
Fixes #93 date picker closes once you pick a date
Merge branch 'flat-ui' of github.com:Gowiem/Sisyphus into flat-ui
Moves login button to only show when logged out
Updates NavBar to not have margin-bottom on home
Updates home screen to have no margin/padding