Virtual consoles kinda work!

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 :^)

Kernel/Syscall.h

@@ -36,6 +36,7 @@ enum Function {
     PosixUname = 0x2004,
     SetMmapName = 0x2005,
     PosixReadlink = 0x2006,
+    PosixWrite = 0x2007,
 };
 
 void initialize();