ok...removed everything from host/memory.ts except for read, write and
size. I have decided (hopefully not incorrectly) that the memory module
acting as hardware should just read and write (and maybe report its
size). I will let the MMU handle errors while reading or writting, and
anything else, including display. Which, with all these display stuff
wouldn't it be fun to create a object like "display" ? But, not now.