Make microblocks work for nodes with layered textures #178
Description
Currently, only topmost layer texture gets picked up and mapped to the side it's on on the original node.
This makes dirt with grass stairs use a stretched-out single-pixel high texture on the sides for instance.
This is a low-priority bug as there are more important things that should be done first though. For now, those nodes are just ignored during registration.
For a list of affected nodes, look at commented out nodes in #176.