Lightweight Java Game Library Code

Fixed typo

Added Pbuffer.isUsingDisplayContext()

Implemented new type of Pbuffer that use the Display context, which is faster than a separate context (Linux)

Make sure VBOTracker reset the current tracker when GLContext.useContext(null) is called

Use WeakHashMap in the static mapping from contexts to vbo trackers in VBOTracker.java.

null currentContext when GLContext.useContext(null) is called

Corrected minor documentation error in GLContext

Added a comment that a context must be current before calling GLContext.useContext()

nuked, content replicated in example

render a square