APC documentation update

Hello APC geeks,

The APC documentation has been updated to reflect current trunk (for =
3.1.4), and hopefully includes all of the information that was missing =
before. Some stuff is probably missing or not awesome, so please have a =
look and update. Note: 9 functions, 5 ini settings, all constants, and =
APCIterator were added.

Documentation is pushed to mirrors every Friday, but the doc mirror =
updates 4x daily. So:

 - http://docs.php.net/apc

Your choices for submitting documentation include:

 - Checkout the doc sources and commit
 - Use: https://edit.php.net/ (beta)
 - Write [email protected] with info
 - Write me with info
 - IRC (#php.doc @ Efnet)
 - Submit doc bugs via bugs.php.net
 - Add user comments to the appropriate man pages

And feel free to deviate from the structure with new pages or sections =
(e.g., "Gotchas", "Performance tips", "FAQ", "Examples")

Regards,
Philip