… now that we have a better idea about the differences of both classes.
Also, no transitive dependency on bos.hpp for either class.
Part of P0120, funded by Yanga.
No idea why ZUN split the 6 slots into 4 with a regular alpha plane,
and 2 with a negated alpha plane. The latter are only used for Sariel's
animations.
Part of P0095, funded by Yanga.