New API for moldy

Please, read carefully all the tests. It is quite a major change.

-> All the tests are passing.

I have split the "object" and the "moldy" part in 2 distinct parts. One responsible for dealing with the schema and fetch "objects" and the other acting as a "base Model" for each object created by Moldy.

I think it solves a lot of concerns I had with an object which has a "save" and a "collection" method on the same level.

If you read the code, you will see that some parts has been commented due to that decision ( because it is not more needed ). If you look at the tests, I think the API is much more coherent then before.

cheers...