GLContext: Make 'deviceVersion' fields final. Reviewed by Harvey.
FontConstructor: Hide the exposed strings and add them in class API doc to minimize footprint. Review of Harvey.

Since accessing the static final exposed strings would trigger static initialization,
setting the properties this way would not work anyways (if not inlined ..).
Well.
Fix Bug 750: Leaked X11 ColorMap for each created X11 Window in NativeWindow (dummy) and NEWT

Free the colormap at WindowDestroy, which we have created at WindowCreate w/ AllocNone.
Due to the fact we used 'AllocNone' the leak is minimal though ..