Fix NULL pointer dereferencing in in Phalcon\Db\Adapter\Pdo::execute()
Fix segmentation fault in \Phalcon\Db\Column::__set_state()
Fix segmentation fault in Phalcon\Validation::getValue()
Merge pull request #772 from sjinks/issue-771

Fix NULL pointer dereferencing in Phalcon\Db\Adapter\Pdo::execute()