Merge pull request #25 from teugis/master

Added summary for question title.
Merge pull request #26 from teugis/master

Fixed context.
Fixed project files.
Merged pull request from plenske/master.
Methods for converting FeedbackEntity added
Added FeedbackManager; updated FeedbackService
Removed unnecessary code, updated conversion code
Processed comments by teungis
Added new custom exception 'NotFoundException'
Removed unused import, fixed error, added includes

Processed the comments of both teugis and daanvc.
Merge pull request #27 from jorisvervuurt/master

Pull request for implementation of FeedbackService.
Merged master repo in my fork.