Dual terminal support

Support for two terminals in the emulator. Closes #19 

Note that sometimes junk and/or the error message `mkdir: can't create directory '/tmp/root-runtime-dir': File exists` will appear in either terminal window; as far as I can tell this is related to how the login process is now handled in `/etc/inittab` and does not affect functionality in any way.

To switch between terminals, press the newly added arrow button in the top right corner of the terminal. Fullscreen state is maintained between switches. `gcc` compilation still happens in the first terminal window, but this can be changed later if necessary.

There is a test setup running on http://tf2.intense.io:9000/#playground
Why did you change this? Based on your hosted test setup, currently what happens is when you switch to full screen on the first (left) terminal, the focus is set to the second terminal -- hence anything you type is sent to the second (right) terminal.
You need to set focus to the terminal on which the full screen button was clicked.