If we're going to linear sample, make sure tex is mipmap complete
Track if transform feedback is active, and ensure we deactivate
Serialise out scissor test enabled bit
Handle arrays of sampler variables. See gl-330-sampler-object
Handle missing format. See gl-330-texture-integer-rgb10a2ui
Don't want to sample mipmaps even when linaer sampling
Add support for texture rectangles. See gl-330-texture-rect
Add support for texture rects & renderbuffers to histogram/minmax
Convert internal format to sized early, for making copies

* When serialising out initial states of textures, we make a duplicate to
  copy into. Since we use the storage APIs we need a sized format, so let's
  convert the format early so the stored internal format is sized. This
  doesn't cause a behaviour change as the impl is free to choose any sized
  format and we're just reading back the choice, and making it explicit.
Support doubles in shader vars natively, not packed in 2*uint32 each
Cheeky add a couple of supported extensions that g_truc looks for
Get chunk names the right way around
Handle invalid index type reasonably gracefully
Include SAMPLER_CUBE_MAP_ARRAY in switch (as any other sampler type)
Handle GL_EXT_texture_sRGB_decode. See gl-420-fbo-srgb-decode-ext
Another cheeky extension
Fix wrong chunk enum being used
More cheeky extensions.
Handle other object label types, and negative message lengths

* If a message length is set to a negative value, the message should be
  treated as null terminated
Mute the spam about supported extension functions not being returned