Add capability to start phantomjs with remote debugger in ruby webdriver

[sj26]

I love being able to use phantomjs as a webdriver in ruby, but miss the remote
debugger which was so easily exposed via poltergeist.

This pull adds the capability to start the phantomjs service with the remote
debugger listening.

Still not sure how to expose this in the actual browser or bridge. Might require
adding another driver extension, maybe HasDebugger with #debug. Thoughts?

(I have signed the CLA.)

[detro]

One thing preoccupies me: because I can't take ownership of all the PhantomJSDriver bindings, discrepancies and functionality mis-matches might become too many in the long run...

[lukeis]

@detro feel free to update them in the selenium tree (you have the commit bit) or you could distribute your own gem or pypi package ;)

[detro]

@lukeis In other words, I have to "chill out" :)

I'm not in the know for either Python (very little knowledge) or Ruby or C#. Hence I couldn't contribute anything useful there. Well, unless I focus on that instead of actually finishing the WireProtocol implementation and fixing the issues.

In other words, "nevermind" :)

[jarib]

Thanks, but I prefer the ability specify arbitrary arguments to the phantomjs executable as suggested here. Closing this.

[jarib]

Looks like I don't have the permission to close PRs. @krosenvold?

[sj26]

@jarib that looks great!

[sj26]

Closed in favor of suggestion in #8.