Add a define in both the source and Makefile for enabling logging of z80 instruction address/cycle counts. Fix Z80 in/out instructions to eliminate assumptions about which registers are stored in native regs. Fix read_16 to not corrupt the low byte when the read has to call into a C function.

--- a/Makefile	Mon May 25 17:08:56 2015 -0700
+++ b/Makefile	Mon May 25 18:56:22 2015 -0700
@@ -16,6 +16,10 @@
 LDFLAGS:=-O2 -flto -lm $(shell pkg-config --libs $(LIBS))
 endif
 
+ifdef Z80_LOG_ADDRESS
+CFLAGS+= -DZ80_LOG_ADDRESS
+endif
+
 ifdef PROFILE
 CFLAGS+= -pg
 LDFLAGS+= -pg