Added phantomjs support to CLI

You can now pass `-b` and it will run your website in phantomjs.

Phantom will parse console until it hits `# ok` or `# fail` which is used to determine that `TAP` output has finished. (this works for tape, have not tested other TAP outputting test modules).

Phantom will correctly bubble an error code and `run-browser` correctly exits with `0` or `1`.

You can now do things like `run-browser tests.js -b | tap-spec`