patch to allow zxsp to use two different Z80 implementations

ZX Spectrum emulator `zxsp`, which includes source from `zasm`,  comes with it's own Z80 emulation class.
We fix the double definition here in zasm, because it is much easier here, though we have to rebase zasm over a lot of commits.
The problem should be fixed more properly later.

Author: Megatokio

Source/Z180.cpp

@@ -292,7 +292,7 @@ static const uint8 cc_z180_ED[256] =
 
 
 
-Z80::RVal Z80::runZ180 (CpuCycle ccx)
+zasm::Z80::RVal zasm::Z80::runZ180 (CpuCycle ccx)
 {
 	CpuCycle cc;			// cpu cycle counter
 	CpuCycle ccx0 = ccx;