Native bindings to the NV_conservative_raster_pre_snap extension.

NV_conservative_raster_pre_snap_triangles provides a new mode to achieve rasterization of triangles that is conservative w.r.t the triangle at infinite precision i.e. before it is snapped to the sub-pixel grid. This extension provides a new mode that expands this functionality to lines and points.

Requires NV_conservative_raster_pre_snap_triangles.