Updated / Fixed PlayerService interface, added essential methods to select and play music from playlist, added ui update for pause button

Fixed FileService constructor, we can't use JFileChooser it's a ui object, a call to new will open a JFileChooser on the screen.
Moved "public final" Constants to interface

Added File real/file name system after file reading in AddToLocalCatalog mehod from MusicService

Implemented optional development : music information edition, updated Music and Catalog for better Observer DP usage.
Added missing parameter "year" to music information at reading

Sorry for all these modif in one commit, I had troubles with a merge and had to clone again the project...