Implement .m3u support and new extensions.

[ArturitoManito]

Added .m3u extension support to the GameResolver for disc-based platforms. This allows modern emulators to handle multi-disc games as a single library entry. Platforms updated: Sony PlayStation 1 & 2, Sega Saturn, Sega CD, Dreamcast, and Nintendo GameCube.
New extensions to Nintendo 3DS: ".3dsx", ".cia", ".cxi", ".cci", ".zcci", ".zcxi", ".z3dsx".
New extension to Playstation 3: ".iso"

[LukePulverenti]

are the m3u's in the same directory as the game? doesn't that cause it to be detected twice?

[ArturitoManito]

Yes, they are in The same directory but, users can rename their multi-disc files to something like Game (Disc 1).chd, Game (Disc 2).chd, etc., and create a Game.m3u as the primary entry point. Then by adding a .embyignore file with the pattern *(Disc ), the server will ignore the individual discs and only list the .m3u in the library. The other games that doesn't have multi disc's Will continue to be found as .CHD.