Added unconditional RET, JP, CALL and RST instructions for Z80.
Added OUT and IN instructions (without effect) and DI and EI instructions for Z80.
Added register IN and OUT instructions for Z80, and mapped opcode 76 to HALT in place of LD.
Added 16-bit LD, SBC and ADC instructions for Z80.
Added RETN, RETI, IM instructions, and LD instructions for I and R, for Z80.
Added NEG, RRD and RLD instructions for Z80.
Added repeatable instructions for Z80.