Fix for compilation error on GLXContextID. Reference : http://eab.abime.net/showthread.php?t=71416
Fixed CMake configuration generating library file names that ld couldn't find when using symbolic names during linking.
GLEW makes its return.

Conflicts:
	extlibs/GLee/include/GLee.h
Updated AUTHORS and CHANGELOG.
Updated README und GUIDELINES files.
Added possibility of specifying during runtime optional character sets for the Renderer to preload glyphs for, added missing override declarations.