Z380 CPU syntax and code generation

Mpm currently supports Z80, Z180. Add new Z380 instructions and 32bit code generation.

Full instruction set is listed HERE

The Z380 instruction set uses a few variations on instruction syntax, for example IXU and IYU representing IXH (upper 8bit register) of IX and IYH (upper 8bit register) of IY.

Allow the alternative 8bit index naming also for Z80 CPU instruction parsing.

New conditional flag names have also been introduced for JP, CALL (Z80) and new CALR instructions, being the same functionality for existing instructions:

Z80 conditional mnemonic	Z380 conditional mnemonic
P	NS
M	S
PO	NV
PE	V

Allow the alternative conditional flag names also for Z80 CPU instruction parsing.

Mpm enables the CPU target with the -mz380 command line option that parses the instruction set for code generation. A -DZ380 symbol is also automatically created for conditional assembly purposes.