Support in-place binary operations ^= &= |= ^^= <<= >>= >>>=

[hsandt]

I've noticed that binary operations were now supported, but not in-place binary operations:
^= &= |= ^^= <<= >>= >>>=

In addition, the in-place integer division is missing: \=

This is based on personal testing and looking at lexer(_test).py

(in practice I also found more operations failing in my use case, such as \. @, %, $, but since they are working in the unit tests I'm running locally, I think this is caused by my specific code, so I'll have to dig this further)
(never mind, this was luamin failing, not p8tool)