They now use interrupts and thus can be blocked on without sitting in a
busy loop. Not sure if they still work perfectly, need to debug. Works
fine with the console "serial" stuff in qemu.
Todo: Investigate further.
* fix some terminal bugs (some, not all)
* add a serial device to the VFS
* fix up serial so it works better
* add a serial-console application
* fix a bug in some other stuff relating to allocations
* change size of the terminal described by toaru.terminfo
* adds a new system call
