[DRAFT, WIP] PSR-5: PHPDoc Standard

This PR represents the current state of affairs with the PHPDoc Standard. Until this description and subject is altered this PR is considered a Work in Progress and not ready for a final review.

All feedback is welcome, please direct this to the PHP-FIG mailing list to prevent noise in this PR. This PSR covers so many subjects that unless the discussions are separated by topic that it will probably be quite impossible to follow in this PR.

I would also request that people open a thread per issue they would like to discuss and not combine several issues in a single mail; this will help to keep noise-levels down in discussions and for me to loook back or filter important information.

TODO items are tracked in the issue tracker for this PSR: https://github.com/phpDocumentor/fig-standards/issues
You can make a PR against the branch in https://github.com/phpDocumentor/fig-standards.

1. I would however insist that the `@return void` remains in the examples; those demonstrate a complete example and not promote one style or the other.
2. The MAY that you are referring to means that a Coding Standard MAY do anything it wants in this regard and thus allows that `@return` must be omitted
3. The section describing void already contains a complete example without void and describes what you propose. It is not even a note but integral part of the section