ZF-4600: Allow Select to be serializable
It's not possible actually to serialize a Zend_Db_Select object, as it encapsulates the adapter instance which cannot be serialized.
Selects should be serilizable as this could use caching queries creation.
I'm working on a patch that acts the same way as Zend_Db_Table_Row : it uses __sleep() to disconnect the select object from the DB. __ wakeup() is used with the registry to look for a Zend_Db_Adapter instance into it to assign it back to the Select object. Additionnaly, a setAdapter() method is also provided.