merged new_gfx into master/trunk

examples/gfx/ambient_occlusion1.py

examples/gfx/ambient_occlusion2.py

examples/gfx/hsc_hemilight.py

examples/gfx/shadow_mapping.py

examples/gfx/transp.py

modules/gfx/pymod/color_by_def.hh

modules/gfx/pymod/export_entity.cc

modules/gfx/pymod/export_gfx_obj.cc

modules/gfx/pymod/export_render_options.cc

modules/gfx/pymod/export_scene.cc

modules/gfx/pymod/export_surface.cc

modules/gfx/pymod/glwin_base_proxy.hh

modules/gfx/pymod/wrap_gfx.cc

modules/gfx/src/CMakeLists.txt

modules/gfx/src/GL/glew.c

modules/gfx/src/GL/glew.h

modules/gfx/src/GL/glxew.h

modules/gfx/src/GL/wglew.h

modules/gfx/src/bitmap_io.cc

modules/gfx/src/entity.cc