Some little improvements in messages

I improved some messages, so that the kernel looks more polished to new users.

v0.2.0

I released a new version, which is what I am shipping soon (if nothing goes wrong). It includes an interactive CLI, which was made possible with the new keyboard driver. I improved the scrolling performance a lot, which I personally really enjoy! Finally, I fixed a bug when printing numbers, so the printed memory map now has (mostly) correct addresses.