fix same-model non-opaque face culling

[KaptainWutax]

This change makes it so models require the same-model neighbor's opposite face to exist before culling. It is a strictly less aggressive cull strategy (anything that was not culled before remains unculled). Also worth noting: DISABLE_CULL_SAME_OCCLUDES appears to do the opposite of what its name suggests and some of the comments may need updating.

Before:

After:

[MCRcortex]

Nice catch on the cause of the error, just the wrong fix. (ModelQueries.faceCanBeOccluded(meta, face)&&ModelQueries.faceOccludes(meta, face^1)) afak is the correct fix (implemented and tested and seems tobe working

[MCRcortex]

faceExists is for stuff like kelp, short/tall grass flowers etc where there is no visible geometry when looking straight down

[KaptainWutax]

Thank you! I misunderstood how faceExists works here. Your fix is much better, appreciate it.