PEAR Package Autoloader

This was a simple experiment to try out the PEAR2 Pyrus API, and see how easy
it would be to install PEAR packages on the fly.

The default channel is pear2, but that can easily be modified by changing
the classToPackage method.

This is pretty dangerous of course, but a fun experiment none-the-less.
http://saltybeagle.com/2009/11/autoloader-that-installs-pear-packages/

@author Brett Bieber <brett.bieber@gmail.com>
@license New BSD