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.

#ifndef GDB_REMOTE_H_
#define GDB_REMOTE_H_
#include "blastem.h"

void gdb_remote_init(void);
m68k_context * gdb_debug_enter(m68k_context * context, uint32_t pc);

#endif //GDB_REMOTE_H_