BRS 0.3.0

In 0.3.0, BRS learns the print statement! Executing a file is actually useful now:

$ cat test.brs
print """The horse says, 'Doctorate denied'."" -- Professor Shpeekenshpell, Futurama S6 E8"

$ brs test.brs
"\"The horse says, 'Doctorate denied'.\" -- Professor Shpeekenshpell, Futurama S6 E8"

There's some obvious printing quirks (namely that I'm lazy and using JSON.stringify to print strings), but those will be fixed in the next release.