Added some javadoc, renamed GET_ALL messageType to GET_CATALOG.
Updates on tagMap system (create local tagmap from local catalog only when needed)
Partially implemented MusicSearchCommandImpl only (remains service and others)
Updated music Class, fixed equals method for usage in collection<Music> and similar
Added some warnings relatives to potential unexpected but avoided behaviour (adding an already existing music (same hash) is forbidden and simply skipped if user is trying to do so)