Add some basic testing using jasmine

Summary:
Make some tests that test the parser. So far, there are no DOM tests,
but maybe later.

Test Plan:
Run `make serve` and then visit `/test/test.html`. Make sure all the
tests pass.

Reviewers: alpert

Reviewed By: alpert

Differential Revision: http://phabricator.khanacademy.org/D2987