Minor adjustments in preparation of the website changes

As discussed on the [mailing list](https://groups.google.com/forum/#!topic/php-fig/CxnuYXtaGlc), I am working on adding the PSR-* localizations to the website. I have therefore applied the following changes to the main repo:

- Wrap the lines in the readme file at about 80 characters (this is just cosmetics)
- Amend the missing PSR-0 headline to the `PSR-0.md` file
- In the readme file, link to the website for the current list of voting members

Feel free not to merge the latter if you want the list to be both on the website and in the readme file. However, then please make sure to update the readme file accordingly, because right the both lists are out-of-sync :)