Drop unused OpenGl_ArbVBO.
Replace OpenGl_ExtFBO with OpenGl_ArbFBO.
OpenGl_Context - reorganize GL functions management.
OpenGl_GlFunctions structure now stores pointers for all GL functions,
while inheritors specify functions subset using access levels.
Drop fields core12, core13, core14; replace extFBO by arbFBO.
OpenGl_ArbIns, OpenGl_ArbTBO - use GL3.1 core functions
instead of ARB extensions when available.
OpenGl_ArbFBO - provide complete list of functions
OpenGl_GlCore11 - fix misprint
OpenGl_Context.hxx - remove redundant declarations
License statement text corrected; compiler warnings caused by Bison 2.41 disabled for MSVC; a few other compiler warnings on 54-bit Windows eliminated by appropriate type cast
Wrong license statements corrected in several files.
Copyright and license statements added in XSD and GLSL files.
Copyright year updated in some files.
Obsolete documentation files removed from DrawResources.
