Let shaders dictate vertex buffer attributes for alpha faces (if shaders are enabled)
Experimental volume face batching changes (Cursory testing shows: +~10% larger mean batch size).
-Drive pass selection by face pools. Doing such removes a fair bit of redundant (and often buggy) code.
-Ignore irrelivant batch breakers depending on pass/pool type.
-Face sorting algorithm modified to potentially allow larger batches.
-Removed a few unused/broken things (bake_sunlight/no_materials)
-Fullbright handling should hopefully be a little more consistent.
-Prevent fullbright faces from being placed in 'simple' pool. (They are already simple-er)

Fixed attribute error that popped up with bump faces when batching was disabled.