Metal Support contributed by Migeran (https://migeran.com) and Stuart Carnie.
Co-authored-by: Stuart Carnie <stuart.carnie@gmail.com>
Co-authored-by: Gergely Kis <gergely.kis@migeran.com>
Properly apply custom materials with CanvasGroups in the GLES3 backend
Properly blur backbuffer when using a partial rect in forward_plus and
gl_compatibility renderers
Properly set fit_margin when clear_margin is set
Fix shader error during backbuffer clear in mobile renderer