Assuming usage with composer

Address issue #2
composer.json not written yet.
Updating to handle CakePHP 2.0 models
Fix references to plugin. Not all plugins are loaded immediately

Note: Image_GraphViz is horribly broken in more recent versions of PHP
Going to swap for something else
Initial stab at composer.json
Conversion for CakePHP 2.0

Use phpDocumentor/GraphViz, since Image_GraphViz is not longer maintained
Modifications for Composer installation