Changes

SWT GLCanvas: Fix sporadic drop of redraw on X11 _and_ allow using custom GLCapabilities on X11 (feature complete)

To allow custom GLCapabilities, we had to use native parenting on X11 w/ a new child window.
The desired visualID chosen by the users GLCapabilities is passed to the new child window.

The redraw drops must be caused by the original GDK or the new child GDK window.
Now we use a plain X11 child window similar to NEWT's X11 window and NewtCanvasSWT,
which doesn't expose this bug.
(Note: SWTAccessor/GLCanvas still contains the uncommented GDK code path for further inspection, if desired)

Also added SWTNewtEventFactory to test event handling on the SWT GLCanvas w/ GearsES2.

TestSWTJOGLGLCanvas01GLn tests custom GLCapabilities now.

SWTEDTUtil has been moved to private: com.jogamp.newt.swt -> jogamp.newt.swt.