Add a few missing opcodes, fix STSWI

The missing opcodes are all probably uncommon.

STSWI was decoding wrong.  I don't think it's common either, though.

Also, update wxWidgets since it was merged.

I've got a separate opcode decoder written and partially hooked up, but not being used yet.  Need to de-virtual the opcode funcs.  The SC change for example is needed since it is more typesafe (and code be even moreso, which I would recommend, e.g. `GPR ra` rather than `u32 ra`.)

-[Unknown]