Bring many of the normalmaps up-to-date
relative to changes that have taken place over the past few months in
their source textures.

Also added some missing normals to go with recently-added textures for
the Undergrowth modpack, so that the fallen leaves, moss, etc. work
right.

Also improved several of the default textures' normals, plus normals for
moreblocks cactus brick, unifiedbricks normals, coloredwood, and a few
misc. related items.