This commit adjusts the capabilities returned
by the SWR driver and the documentation to correctly
report the following extensions:

GL_ARB_texture_query_lod, GL_ARB_texture_cube_map_array,
GL_ARB_gpu_shader_fp64, GL_ARB_texture_gather,
GL_ARB_vertex_attrib_64bit.
Reviewed-by: Alok Hota <alok.hota@intel.com>