Changes

JAWTUtil/MacOSXWindowSystemInterface-pbuffer: Cleanup / More DEBUG info

JAWTUtil.getJAWT(..):
  - better local var names
  - one time init
  - add DEBUG trace
JAWTUtil.<init>:
  - add offscreenLayer info

MacOSXWindowSystemInterface-pbuffer.m:
  - remove warning: access of protected vars from outside class
  - better local var names
  - more DEBUG info (pbuffer texture)

Fix Bug #589 (JAWT Offscreen-Layer resize) and Offscreen-Layer setSwapInterval() deadlock; Reuse JAWT instance; Cleanup

- Fixes
  - OSXUtil.CreateCALayer*(..): Pass layer target size (if known).
    This fixes Bug #589

  - MacOSXWindowSystemInterface-pbuffer.m:
     - ALL: displayLink NULL check

     - setSwapInterval(..): lock only for variable setting,
       could deadlock when start/stop CVDisplayLink

  - JAWTWindow.destroy(): use 'surfaceLock' instead of 'synchronized'

- Cleanup / Performance
  - JAWTWindow.lockSurface(): Reuse JAWT instance

  - MacOSXJAWTWindow: AttachJAWTSurfaceLayer0(..) -> SetJAWTRootSurfaceLayer0(..)
                      Reflects semantic better.

- DEBUG
  - JAWTWindow.updateBounds(..) notify of bounds change