Rename numbered tests to something more descriptive - closes #16

test077 is the only one I really couldn't figure out what it was meant to test. If you can explain what it tests in a comment to this PR, I'll rename it and update this PR.

I've added "closes #16" in the commit message in hopes that Github will automatically connect [issue #16](https://github.com/espruino/Espruino/issues/16) to this pull request.