Feature/mg/testing

- created a grunt task `test` to only run tests (more or less everything which is in build)
- added some additional reporters for the frontend test results (results can be found in `/out/test/frontend/` and in the console)
- package.json is now ordered (was done automaticially)
- added song filter to filter out inactive songs
- added tests for search request and some adjustments out of the testing
- adjust backjump to the first page, to do it if we have received the results