Extended the SFML library to support MP3
This works in two ways: 1) by direct streaming or 2) by encoding the file to 32bit WAV on-the-fly and completely loading it into the buffer (not recommend). Fusee supports 23 formats now: mp3, ogg, wav, flac, aiff, au, raw, paf, svx, nist, voc, ircam, w64, mat4, mat5 pvf, htk, sds, avr, sd2, caf, wve, mpc2k, rf64