Add knobs necessary to expose texture storage emulation
Leave glTextureStorage calls to DSA, implement glTexStorage calls in TexSto emulation
ARB_texture_storage mostly working (needs error checking)
Implement tracking of immutable textures created with ARB_texture_storage
Fix gcc compile errors
fix hard coded number of texture targets
Disable Emu::So if GL_ARB_sampler_objects is available.
For github issue #73
Merge pull request #3 from p3/nstewart

Disable Emu::So if GL_ARB_sampler_objects is available.
proposed fix for issue #74, lookup texture name from active texture + bound state
Automatic context sharing for GLX
JSON support for Config::enableTrace
Further push/pop attrib emulation support
Merge from git://github.com/jra101/regal.git master
Merge from https://github.com/p3/regal.git cass
Further push/pop attrib emulation support.
Improved multi-threading, shared contexts for GLX.
Updated VC projects.
More Regal::Emu::Ppa (push/pop attrib) support.
glGet support for Emu::So.
Minor bugfixes.
Merge branch 'master' of git://github.com/p3/regal.git