ReflectionType improvements

Now that the mailing list is working again I'd like to propose some improvements to the ReflectionType API. We added ReflectionType as part of the Return Types RFC. At that time the API was intentionally kept minimal to not step on the toes of potential future features (such as enum, union and intersection types) with the intention of fleshing it out later. As long as the release managers for 7.1 are okay with it I'd like to do these improvements now. Shall I move forward with an RFC or do you consider this too late? The proposed API looks like this: https://gist.github.com/morrisonlevi/5819a2b8d86561849ee916a7bcbc9c29. Notably a `ReflectionClassType` will be returned if possible which has a `getClass(): ReflectionClass` method. This has been a commonly requested addition and simplifies a common use-case. I tried to discuss these changes on Reddit to gauge community impact but it had few responses: https://www.reddit.com/r/PHP/comments/4m93s1/i_want_to_enhance_and_break_the_reflectiontype/.