Redesign the availability page to fit impot of availability.
Modified few design details. Implemented correct selection and submission of export and import
Renamed Availability download controller to export controller. Added Import controller.
Added route to import. Modified route to export.
Made self-update
Added selection of availability for a TA based on a day as well.
Modified TAs view to match format of availability view
Merge pull request #45 from andreykul/issue-44

Finished Issue 44