Added sidebar with calendar.

Calendar has dayClick functionality which sends alert with moment()
object.
Added file-export possibilities.
Added file-import.

File import now works if the input is exactly as the output.
Observer implemented for when calendar chooses day.
Added observer to activityGridController
Added schedulerView to mainController
Hid schedulerView in mainController
Fixed linux issue
Merge branch 'master' of https://github.com/Unic0arn/2Day
Fixed overlay and scrollbar