[dev] @category tag

[Mike Naberezny]

Hi All,

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".

Mike