Merge pull request #47 from creydr/master

Small changes from our meeting today
Merge pull request #48 from creydr/master

added german language support
[ADD] Introducing the notification system
Merge pull request #50 from creydr/master

added better error messages on adding a loanable
[ADD] Fixing notifications issues and merging documents
Merge pull request #51 from Akhilian/master

Adding a notification service.
translated the notification string in german and english