[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
@mvriel knows I've badgered him on this a couple of times before - my thoughts are at http://code.garyjones.co.uk/why-return-void-is-wrong

I guess the complaint here is that you're saying both schools of thought are equally valid (and you're right), yet PSR-5 clearly favours one over the other ("recommended").

If PSR-5 said something along the lines of "...*MAY* use `@return void` or MAY omit it altogether..." and not "...recommended to use `@return void`...", then I think the majority of those in the _omit_ school would be happy.