Remove some debugging.
Merge pull request #13 from metajack/gpu-rendering

Remove some debugging.
Remove AutoContextRestore.
Add linux support to Skia build.
Add support for CFG_ENABLE_DEBUG to Skia.
Merge pull request #14 from metajack/linux-gpu

Add linux support for Skia shared GL contexts
Destroy framebuffers, textures and renderbuffers when the context dies.
Merge pull request #15 from metajack/fix-texture-leak

Destroy framebuffers, textures and renderbuffers when the context dies.
Fix shared GL context destructor to free correct texture.
Merge pull request #16 from metajack/free-tex

Fix shared GL context destructor to free correct texture.
Set SK_RELEASE and GR_RELEASE on non-debug builds.

If these aren't set then Skia will compile in debug mode by default.
Merge pull request #17 from metajack/debug-fixes

Set SK_RELEASE and GR_RELEASE on non-debug builds.
Merge remote-tracking branch 'upstream/master'