Add support for to PhantomJS

It doesn't pass the tests using PhantomJS as browser, however,
I'm pushing this out because Chrome doesn't pass the tests
either, only Firefox so I assume they need to be fixed.
Nevertheless, I tested it out on a project I'm working on and it
seems to work fine.
Merge pull request #33 from aristidesfl/phantomjs

Add support for PhantomJS