Merge pull request #18 from adamarla/master

edits for menu items
Edited link text
Allow even non-dropdown links to have an associated icon
Added icons alongside .dropdown > li > a

Visually suggesting what the action would entail
icons added for logout / edit account links
Minor edits to tutorials
Changed icons for menu items
Remove formtastic, carrier_wave & spreadsheet gems

In the process, a lot of redundant partials also get removed
Modified code for file uploading - not using FormData()

Got rid of carrierwave. And therefore doing sanity checks on mime-types internally
Doing away with carrierwave and therefore ability to upload student list as .xls

Teachers now create sektions and students enter the supplied sektion code
to enroll in one
- adjustments due to change in the way suggestions are stored
Merge remote-tracking branch 'heroku/master'