Xpdogenerator

New pull request for xpdogenerator. Adds a final argument to writeSchema() to allow user to send a string with a comma-separated list of tables to process or an array of arrays of tableNames=>classNames.

$tableList = 'table1,table2';
or
$tableList = array(array('table1'=>'classname1'),array('table2'=>'className2'));

To make sure the original code executes if the $tableList argument is omitted, I ran the old code and the new code on the entire MODx DB with that argument omitted and the diffed the resulting schema files -- they were identical.