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.

`hdgcc-mod.bz2` (the disk image) has been modified to start `getty` on boot. `/etc/inittab` and `/bin/autologin` were modified to achieve this.

There is a test setup running on http://tf2.intense.io:9000/#playground
I see your point. However, the way I see it is that you are supposed to use the hardcoded constants. The jor1k codebase, `sys-runtime.js` and `live-edit.js` all use these string constants to refer to the ttys. These should ideally be global constants/enums or something instead of strings. If you want to use the element ids to refer to the ttys then the ids should be constants - the element ids shouldn't then be passed in as parameters to the Jor1kGUI constructor. What happens if the HTML programmer uses some different ids and passes them to the Jor1kGUI constructor? The very fact that the ids are accepted as params means that we cannot rely on them being the constants we expect them to be. If you want to get rid of the constants entirely, then you'll need to modify jor1k itself or somehow map from the term ids to the constants. This was just my opinion, what do you think?

Anyway, no changes are required, I just merged in your code.