Resolution of X11 key-repeat handling

Resolution of X11 key-repeat handling

glutSetKeyRepeat is global to all FreeGLUT windows in the application
glutIgnoreKeyRepeat is a per-window over-ride

To avoid nasty global X11 state interaction, or GLUT-style
event queue filtering - the approach in FreeGLUT is to
use the current key state XQueryKeymap to detect and
ignore KeyRelease/KeyPress pairs that are auto-generated.

See also:
http://pyopengl.sourceforge.net/documentation/manual/glutSetKeyRepeat.3GLUT.xml
http://pyopengl.sourceforge.net/documentation/manual/glutIgnoreKeyRepeat.3GLUT.xml

git-svn-id: svn+ssh://svn.code.sf.net/p/freeglut/code/trunk/freeglut/freeglut@476 7f0cb862-5218-0410-a997-914c9d46530a