[dev] @category tag

[Chuck Hagenbuch]

Quoting Mike Naberezny <mike at naberezny.com>:

> Currently we use @package in our files but no @category.  I've noticed other
> projects are now using @category such as "@category Solar".
>
> It's a trivial change but could be useful, especially for projects that mix
> libraries from different frameworks in a single PEAR-style directory.
>
> Thoughts?  If there's no objections, I'll offer to add the "@category Horde".

I'm fine with this.

-chuck