- introduce Generator feature
- new fetch* methods of MDO\Select: fetchAll(), fetchAssoc(), fetchDataObject(),fetchFunc(), fetchPairs(), fetchCol(), fetchAssocMap()
- new yield* methods of MDO\Select: yieldAll(), yieldAssoc(), yieldDataObject(), yieldFunc(), yieldPairs(), yieldCol(), yieldAssocMap()
- new get_Generator() / get_Array() methods of MDO\Statement
- deprecate iterators
- require php 5.5+