Native bindings to the NV_conservative_raster extension.

This extension adds a "conservative" rasterization mode where any pixel that is partially covered, even if no sample location is covered, is treated as fully covered and a corresponding fragment will be shaded.

A new control is also added to modify window coordinate snapping precision.

These controls can be used to implement "binning" to a low-resolution render target, for example to determine which tiles of a sparse texture need to be populated. An app can construct a framebuffer where there is one pixel per tile in the sparse texture, and adjust the number of subpixel bits such that snapping occurs to the same effective grid as when rendering to the sparse texture. Then triangles should cover (at least) the same pixels in the low-res framebuffer as they do tiles in the sparse texture.

Requires GLES 2.0.