added Doctrine_Connection::delete() method (needed as a convenience method as well as for the upcoming CTI support)

Fix array_merge so that schemas that are loaded after are merged in to the existing array of schemas.

called in Doctrine_Connection_UnitOfWork->delete().

Rewrote data loading to support I18n data, nested set data, and better relationship defining for fixtures. Also fixes ticket:528

Fix to toArray() when you use toArray(true) on a record that has not been saved yet but has references