PHP MySQL Caching Wrapper: Execute MySQL queries and cache results in files

This is my first contribution, i took several classes from here and would like to give some back. Maybe someone can use as i did.
I needed for some customer projects a mysql wrapper who caches mysql database queries. Another approach was that if database connection fails , the cached result will be returned.

The class had to be runable under php4/5.
So this is a quick result. use it as you like.

if you use this with php < 5.2 you need json.class.php
http://pear.php.net/pepr/pepr-proposal-show.php?id=198


History:
     08.12.2010 - Version 0.1 finished
     12.12.2010 - Implemented Class Registry
     31.12.2010 - Implemented Event Handling -> v 0.2


Todo:

	Blacklist queries who cannot be cached