Bug fixes for sound API and native library loader; Updates for world package and Sound API

-Fixed bugs in class Local (native library loading)
-Fixed a bug in Snap2D SoundAPI library loading
-Added SoundAPI and modfied Snap2D sound API structure
-Added World2D
-Half-implmented Entity class
-Changed package com.snap2d.context to com.snap2d.world
-Modified native library loading system
-Moved old builds to root directory of project
-Added LICENSE and COPYRIGHT text files

I don't recommend building off of the Entity implementation yet.  It's
still a work in progress and is subject to significant changes.  The
World2D system, however, is good to go.