Modified protractor to support testing node-webkit by using string conca...

I wanted to create a pull request for #1266 in case there was a chance it would be accepted.

When using AngularJS in https://github.com/rogerwang/node-webkit, the browser uses `file://` based urls.

The `baseUrl` in the protractor config is stripped when it begins with `file://` because it is run through `url.resolve`.

This commit simply concatenates `baseUrl` and `destination` when the `baseUrl` begins with `file://`, otherwise it joins the variables with `url.resolve()` as normal.

This is the only issue that prevents us from running tests with protractor in a node-webkit project.