Bit of an image change

Be more verbose about the structure and concepts of notos in the README.

Drop the C proto-source files.

Add an INSTALL file for a little joke. Charme is everything today ;-)
Go to long mode, indeed!

We have a 64-bit GDT and IDT, paging and are officially in long mode,
hopefully. At least, we can manipulate the screen with 64 bit code.

qemu gets the computer 1024 MiB memory which are identity-mapped with 2MiB
pages. Now, I think, we can do something with that machine :-)

All CPUs will have to be activated, though, and other stuff is pending but
Intel manuals and linux-0.01 are a great help. The latter now not anymore
but good to know anyway.

BTW, rewrite Makefile to use tmux, instead of screen, facilities.