Changes

X11: Harden usage of 'XGetWindowProperty(..)' and 'XGetVisualInfo' - Add missing XFree(..) calls and argument checks.

[Jogl|Nativewindow|Newt]Common: Align all *Common_GetJNIEnv()/_ReleaseJNIEnv() Methods and Usage / Check arguments ..

Since we still don't use inter-module native code sharing, align the JNIEnv get/release methods and usage.

Most beneficary here is OSX and the GLDebugMessageHandle,
both managed the JVM handle on their own - removed now.

Also ensuring that *Common_init(..) is called for all modules on all platforms.

Misc Cleanup: JAWTWindow: Reusing visible in HIERARCHY listener; Remove obsolete 'getPrivateGraphicsConfiguration()'

Fix GLDrawableHelper.resizeOffscreenDrawable(..): Do nothing if !drawable.isRealized() - similar to it's recreateDrawable() and test only _after_ having the surface lock!

Only after the surface lock we are thread safe.

In case drawable has been pulled, do nothing ..

Bug 937 - JAWTWindow: Unsatisfying Visibility Computation

Simplify JAWTComponentListener's HierarchyListener:
  - Don't interfere w/ Component's visibility anymore!
    This shall reduce sideeffects.
    Utilize 'isShowing' in each Component specialization, i.e. GLCanvas.

  - On SHOWING_CHANGED if a parent caused a change
    of the tracked components showing state,
    propagate it to the offscreen-layer!

  - Remove all other complicated states!

GLCanvas, GLJPanel:
  - Instead of 'isVisible()' use 'showing state',
    since only the 'showing state' reflects 'true' visibility
    throughout the hierarchy.

  - Add HierarchyListener and track volatile showing state
    to be used instead of 'isVisible'.
    Using a cached showing state is more efficient
    than quering 'isShowing()' all the time!

NewtCanvasAWT:
  - Use 'isShowing()' instead of 'isVisible(), see above

AWTParentWindowAdapter/AWTRobotUtil: Use 'isShowing()' instead of 'isVisible()' determining actual on-screen showing state

See commit 071bdd6ce9f8c41ccecdbf8bc74f276ccd7ff651

DefaultEDTUtil: At EDT finish, notify all task-waiter to avoid deadlock at error / Add test method 'invokeAndWaitError(..)'

JOGLNewtAppletBase: Typo of new PNG icons .. used AE's 'gray' instead of BE's 'grey', which is used for the filename

Same as 42d3b31d1becd8eb8e2847c87e14e47e15e730cd

JAWTWindow.JAWTComponentListener: Minor Cleanup

OSXMisc CALayer::FixCALayerLayout: Fix visible:=false case, i.e. don'r override cached visibleOpacity w/ forced zero when called twice