POSIX_C_SOURCE def not required

Header cleanup

fix example (projection matrix aspect ratio)

Remove range checks for gpu.offscreen.new

Check non-negative still allows zero height, or INT_MAX... just let OpenGL handle the error case.

Remove args from class

Minor updates to the example

- Add cancel() callback so exiting doesn't leak memory.
- Use staticmethods where 'self' isnt used.
- One line comment explaining what it does.

From review: rename: color_object > color_texture

Remove ofs->framebuffer_object (no real need for it at the moment, we can readd later if someone needs it)

Merge remote-tracking branch 'origin/master' into framebuffer

GPU python code example

Merge branch 'master' into framebuffer

GPU Off-Screen Buffer now linked from API docs

Remove error prefix for use-after-free.

This case is rare enough under regular use,
and Pythons stack-trace to the line is enough to find the error.

Rename PyGPUOffScreen -> BPy_GPUOffScreen

Generally Py prefix is kept for CPython API

Also added the GPUOffScreen class to the module so it can be accessed for documentation.

Projection and Modelview matrix were swapped

Pydocs: include view3d and region

Make samples an optional argument, default to 0

Use Py formatting for GPUOffscreen class

Correct names of RNA types

Also order args: scene, v3d, region...

Remove redundant args to PyExc_Format

Also make error handling more compact.
and don't overwrite errors from PyC_RNA_AsPointer.