adding 2 new extras: mp3_decode and soundfont

- updating version number
- extras now have minified versions as well
- adding timbre.mp3_decode.js in the extras folder
- adding timbre.soundfont.js in the extras folder
- adding jsmad in the extras folder
- adding test.mp3 in the misc/audio folder
Merge branch 'skratchdot_extras' into gh-pages
rebuilding docs