RFC: Return Types Update

Dear Internals, I finally have a working implementation for return types RFC[1] built on top of master. There are a few notes in the PR[2] about the implementation. I invite you all to review the PR and provide feedback. This means that I will soon move the return types RFC to voting phase. If you have not yet had time to review the RFC recently I invite you to do so now. The RFC has been slightly altered since the last discussion: - The RFC now targets PHP 7 (previously PHP 5.7). - There is a new section about disallowing return types on certain methods[4]. - The design and accompanying section of reflection[3] has been rewritten entirely. Regardless of the result of the RFC, I want to thank the many people who have been helpful to me as I have learned php-src and iterated over this RFC. [1]: https://wiki.php.net/rfc/returntypehinting [2]: https://github.com/php/php-src/pull/820 [3]: https://wiki.php.net/rfc/returntypehinting#reflection [4]: https://wiki.php.net/rfc/returntypehinting#methods_which_cannot_declare_return_types