added express validator (same as LF)
post route for playlists
added _id to passport.js users because i need them later on
implemented get requests
put of a song
created delete method
autoformat
changed status codes
also fixed that i cannot make update on ressources i do not own
added check that the owner_id of the song must be set and it must be set to the user wanting to post the ressource
Merge pull request #10 from songster-project/restapi/playlist

Restapi/playlist
added side menu
fix side menu css and auto format html
Merge pull request #14 from songster-project/feature/MG/side_menu

Feature/mg/side menu
disable uglify in Gruntfile, because this leads to an js error. this will be fixed later.
added dependency for supertest
added script for import and export database data, and added exportdata to gitignore
added integration test example
added test script
made test scripts executeable by travis
added mongodb to travis service