Merge pull request #36 from socia-platform/26_NotificationRefactoring

26 notification refactoring
#35 quickfix group edit layout bug
pw placeholder
Delete deprecated list.scala.html and set debug output to false in notification.js
Merge remote-tracking branch 'origin/QuickFix' into QuickFix
refactor README
Merge branch 'QuickFix' of github.com:socia-platform/htwplus into QuickFix
Remove unnecessary Notification.findUsersWithDailyHourlyEmailNotifications() trigger
refactor mail login error message (dedicated to Ryad)
nullpointer deletePost
Create GroupAccount link in controller rather than in the recipient getter for notifications.
Merge remote-tracking branch 'origin/QuickFix' into QuickFix
This commit enables a "read all" feature for notifications.

Classes:
- NotificationController: Add method readAll()
- Notification: Add method markAllAsRead()

Templates:
- menuitem.scala.html: Add div for readAll

CSS:
- htwplus.css: Increase max-height for hp-dropdown-search

Other:
- messages: Add i18n for show all and flash
- routes: Add route for NotificationController::readAll()
Merge branch 'QuickFix' into develop