Merge branch 'master' of github.com:jonaswisplinghoff/arsnova-flashcards
implemented export api call, rough ui integration
added fileSaver to download json export
addded json import
styled input file form
minor design fix
added filetype check
added more useful help popup to import form
added csv import
some more security checks
Merge commit '3b825cc3faf894ceb5e690d3652347f3470dab6b'
Merge pull request #5 from jonaswisplinghoff/master

Import/Export