Can't use phantomjs.cli.args in webDriverCapabilities

Looking at the source code of ```org.openqa.selenium.phantomjs.PhantomJSDriverService#findCLIArgumentsFromCaps```, it seems that it expects the capability to be in the form of either ```String[]``` or a ```Collection```. As the type passed by ```jasmine-maven-plugin``` is always ```String```, this test will always fail and thus it is not currently possible to specify ```phantomjs.cli.args```.

This could perhaps be seen as a bug in PhantomJSDriverService, which should allow a String to be used as a single argument.