added error page template and util view for use in ajax error callbacks
added errorView to error handlers in library logic refs #30
added errorView to error handlers in mensa logic refs #30
added errorView to error handlers in room logic refs #30
passing error to view and logs the stack into console
added errorView to error handlers in sitemap logic and added error-placeholder to view refs #30 refs #90
added errorView to error handlers in transport logic refs #30
Merge branch 'adding-errorHandlers' of https://github.com/University-of-Potsdam-MM/UP.App into adding-errorHandlers
Merge pull request #92 from University-of-Potsdam-MM/adding-errorHandlers

Adding error handlers