(Don't) use this to implement short-form output in ls.
I'm too tired to make a nice column formatting algorithm.
I just wanted something concise when I type "ls".
After I made stdio buffered, we were dropping anything unflushed on exit.
Since /bin/clear just prints out some escape sequences without a newline,
the entire buffer was being discarded.
Also add VirtualConsole::clear() that handles clearing of background VC's.
Instead of memcpy'ing the entire screen every time we press enter at the
bottom, use the VGA start address register to make a "view" onto the
underlying memory that moves downward as we scroll.
Eventually we run out of memory and have to reset to the start of the
buffer. That's when we memcpy everything. It would be cool if there was
some way to get the hardware to act like a ring buffer with automatic
wrapping here but I don't know how to do that.
I'm still playing around with finding a style that I like.
This is starting to feel pleasing to the eye. I guess this is how long
it took me to break free from the habit of my previous Qt/WK coding style.
We now make three VirtualConsoles at boot: tty0, tty1, and tty2.
We launch an instance of /bin/sh in each one.
You switch between them with Alt+1/2/3
How very very cool :^)
