Move duplicated Constraint generation code to the abstract parent
Move duplicated Constraint generation code to the abstract parent

Splits the specification into two parts; the named part (for table
constraints), and the rest (the table/column constraints)

settermjd/zend-db,Koopzington/zend-db,turrsis/zend-db,xorock/zend-db,pikariop/zend-db,mwillbanks/zend-db,MadCat34/zend-db,srayner/zend-db,turrsis/zend-db,srayner/zend-db,robertboloc/zend-db,robertboloc/zend-db,Koopzington/zend-db,jkhaled/zend-db,settermjd/zend-db,MadCat34/zend-db,zendframework/zend-db,mwillbanks/zend-db,xorock/zend-db,zendframework/zend-db,pikariop/zend-db,jkhaled/zend-db