Material archives already contain two version chunks (post process and
normal) but the renderer was ignoring these. The change makes it so that
matc writes a new MaterialEnums value into these chunks, and the engine
panics when receiving a material version that it does not expect.
This also adds a --version option to matc. No changes were necessary
to matinfo because it already prints out these values.
Fixes#796.
e60744a6e4