Functions read and write to disk sector refactored
sysfun.c
	read_sector(arg1, arg2, NULL, NULL) and
	write_sector(arg1, arg2, NULL, NULL) are now
	access_sector(arg1, arg2, RW, NULL)
utils.asm
	_read_sector_raw and
	_write_sector_raw are now
	_access_sector_raw

	unsued code removed