Prevent displaying app if user is not logged in

fixes issue #18
Add ng-file-upload
Add global clicakable global css class
Implement Assetmanagement

Includes:
- Tag creation
- Image Upload
- Assigning of Assets to Canvas
- Removing of Assets from Canvas
Merge pull request #43 from onurv12/master

Fix issue #42
Merge pull request #45 from tobiasmuecksch/master

Prevent displaying app if user is not logged in
Fix "back to project" button in canvasView

Please don't ask me why. But this only works correctly if those dependencies are loaded twice... Once before and once after angular.js.
Improve "go back to project" button in canvasView
Prevent editing Projects that the user may not

edit because he is not enrolled...
Merge remote-tracking branch 'upstream/master'
Add code to add/remove/show comments
Merge branch 'upstream/master' into comments
Fix login management

fixes issue #48
Merge pull request #46 from tobiasmuecksch/master

Implement Assetmanagement
Fix previous commit...
Merge pull request #49 from tobiasmuecksch/master

Fix previous commit...
Merge pull request #47 from boom1992/comments

Add code to add/remove/show comments
Implement deleting of users
Make admins and mods able to change usernames and full names, tweak visibilities