Changed Response class mapping, so the user can 
define its own Response class extending the default one
and choosing type of inheritance (in ORM).
Bugs in mongodb documents mapping fixed.
Optimization: Enable the Response class mapping 
listeners only if there are more than one class,
counting default ones and user defined ones.
Added the possibility of add a prefix to tables or collection names
Changes to apply right coding style
Merge pull request #8 from magarzon/dev

Dev