Seperate JMP and DAT instructions into their own classes. JMP can genenerate "XOR PC, a" instructions.

Signed-off-by: Josh Kilmer <srjek2@gmail.com>
Allow jmp to work with instructions that can't be shortened

Signed-off-by: Josh Kilmer <srjek2@gmail.com>
PetriOS.dasm uses jmps whenever possible

Signed-off-by: Josh Kilmer <srjek2@gmail.com>