Changes

X11Util: Catch X11 Error on XCloseDisplay

*GLContext: resetStates(); getPlatformExtensionsString(); GLX/WGL NV_swap_group support; setSwapInterval();

resetStates()
  - fixes a bug where X11GLXContext impl. resetState() !!
  - marked all with @Override tag
  - ensured super.resetStates() is called at end (oops)

getPlatformExtensionsStringImpl()*
  - fixes a bug where X11GLXContext overrides GLContext cached GLX extension string query
  - marked 'final' in GLContext to avoid bugs
  - using abstract 'getPlatformExtensionsStringImpl()' called by ExtensionAvailabilityCache

Add premiliry GLX/WGL NV_swap_group support
  - thought it might be a solution to sync swap of 2 windows
  - none of my drivers/platforms support it, event though extension is avail on Linux

Promote setSwapInterval() (1 up)
 - bumped above API up to public GLContext
 - those extension should not spam the GL interfaces .. hmm

NEWT: Window default pos ; FullScreen

- FullScreen
  - lock parent window if child
  - X11: more sophisticated EWMH FS usage
  - X11: set window 'Above' before FS and at focus

- allow window WM default position at window creation
  - default position { -1, -1 } as hint to native WM
    to gather a suitable default position
  - wait until user-pos or WM-pos reached

- reconfigureWindow*
  - allow -1 values for pos/size to mark no-change

test scripts

disable test of NV swap group - but add explicit test case (disabled) for documentation purposes