Added function array version of executer and implemented modular instruction processing
Implemented function array for instruction modular processing
Merge branch 'unaligned_access' of https://github.com/alvieboy/xtc-base into unaligned_access

Conflicts:
	softsim/cpu.h
	softsim/executor.c
Changed from executer.h to executor.h
Added cpu.c to handle cpu basic functions
Merge branch 'unaligned_access' of https://github.com/alvieboy/xtc-base into unaligned_access

Conflicts:
	softsim/executor.c
Merged from lastest changes in main branch
Fixed npc issue and changed to new implementation