Update README.

The README file mentions mp3, ogg/vorbis, aac and wma, but speex,
flac and ogg/opus were all missing.  Do not even try to list the
supported audio formats, it always gets out of sync.

Secondly, since this file will not be processed by grutatxt, it's
pointless to format it according to the grutatxt syntax.

Finally, this change adds the URLs of the web page and the git
repository, as well as my email address.