Dialog to allow user to log in to third parties

Creates the ability to have a dialog pop up when a user wants to log in to a third party to interact: e.g. disqus, youtube, instapaper, etc.
@diracdeltas the consequence of breaking ABP compatibility is that the chrome version is still dependent on ABP code for it's blocking engine. I have a long term plan to remove this dependency but for now it's still there.  We could break ABP compatibility and write some glue to turn the list into something that is abp compatible, but that seems unnecessary IMO. 

I agree that it should be hosted somewhere instead of included inline. For now I think it should be hosted as a separate file. I will work on that.