1178518a68
This merges changes in internals, runtime-only of existing custom normals code, which make sense as of themselves, and will make diff of soc branch easier/lighter to review. In the details, it mostly changes two things: * Now, smooth fans (aka MLoopNorSpaceArray) can store either loop indices, or pointers to BMLoop themselves. This makes sense since in BMesh, it's relatively easy to get index from a BMElement, but nearly impracticable to go the other way around. * First change enforces another, now we cannot rely anymore on `loops` being NULL in MLoopNorSpace to detect single-loop fans, so we instead store that info in a new flag. Again, these are expected to be totally non-functional changes.