Casper tests

@AlexeyMK @matteodem @yefim 
We actually have some tests now!

I'll keep writing more, and feel free to add to them.

I'm cool with just having one big file with all the tests, but I'm open to other suggestions.

Also, take a look at run_tests.sh. After running it `Terminated: 15` gets printed to the screen. I can't figure out how to stop it. That's what all the various `> /dev/null` are trying to do.

@matteodem Can you write some tests for the custom menu items when you have the time? I don't know that part so well.
This relative path is going to be _interesting_. Is there no way we can make it point to the Houston in the parent directory here, instead of rely on `Code`?