Create DoctrineHydrator

This hydrator propose a common feature with the Zend/Stdlid/Hydrator/ClassMethods. It's support the option for using name with underscore and can be usefull when the both hydrators are used in differents cases with the same form.

By this way, the common pratice of Zend Framework Stdlib hydrator and the DoctrineModule's one were homogeneous.

It's a simple copy/paste of this two hydrator in a new file.