re-implements a variant on https://github.com/GarageGames/Torque3D/pull/710
preserves deferred render targets unless the format or size was altered
WORKAROUND: very much not loving this 'fix', but since we we're hitting the caps on samplernames, bumped TEXTURE_STAGE_COUNT up from 16 to 32, and sgMaxTerrainMaterialsPerPass down from 12 to 8 (again, 8 is the result of polling artists about thier terrain creation toolsets, so really do not want to push that lower. unless we can figure out how to re-implement multi-pass terrain creation in a deferred manner)