Updated phantomjs dependency.

[Kreozot]

Plus added workaround for regression in phantomjs 2.0.0 (on Windows).

[Kreozot]

It's strange that test has failed. I think, it depends on platform and phantom version. If you compare actual and expected png-s - they completely the same. But for some reason bytes of these files is not the same.
I was testing master branch before and it failed. Then i tried to fix it by 84de565 commit - it fix tests on my machine but not on Travis.

[Kreozot]

I just put files generated on linux and tests has passed.

[justim]

The different expected images are not unexpected, different versions of PhantomJS yield different output, as long as they look the same, we're good.

Just using the following works just fine on a mac.

var sourceUrl = 'file:///' + source;

Does this also work on linux?

If it does, we don't need the workaround and we can just use the file:/// prefix.

And lastly, the path.resolve introduces an issue that was fixed a little while back (#17), so we need a better solution for this.