Use the ORM more efficiently

[brainwane]

As Alvaro said in IRC, the ORM integration (with Storm) is "duplicating code, creating an unneeded layer with *DB objects." This doesn't use the ORM in the best way, since "the idea with object databases is that objects are directly stored in the db, not that you need to create another layer with the db objects. I have reached this conclusion working with new backends ... and having to duplicate a lot of code for persistence."

To fix this we would change the backends - or refactor per issue #39 and do it once in the Backend class.