core/apiRouter, api: initial commit of martini -> negroni port
api/art: martini -> negroni
core/apiRouter: re-enable art routes
api/artists: martini -> negroni
api/folders: martini -> negroni
api/lastfm: martini -> negroni
api/login: martini -> negroni
api/stream, api/transcode: martini -> negroni
api/logout: martini -> negroni
api/search: martini -> negroni
api/songs: martini -> negroni
api/status: martini -> negroni
api/art, artists: fix test regression
api/lastfm: fix test regression
core/apiRouter_test: martini -> negroni, added more tests
core/apiRouter: fix authentication bypass from defer
Merge branch 'dev_negroni'