Add jPlayer 2.7.1 patch to fix mp3s not playing on Android OS.

Modify vwf.js to point to 2.7.1 version of jPlayer.
Remove the old jPlayer 2.7.0 library.
Merge pull request #402 from virtual-world-framework/branches/jplayer2.7.1-mp3-android-bugfix

Add jPlayer 2.7.1 patch to fix mp3s not playing on Android OS.