[#425] Fix Dataset.query() when called with Query model

The problem is that Backbone >= 0.9.9 doesn't accept updating models with:

    model.set(otherModel);

That needs to be changed to:

    model.set(otherModel.attributes);

Dataset.query() accepts both regular JS objects and Query models, so we need to
check the parameter type to support both.
Merge pull request #426 from vitorbaptista/425-fix-model-set-in-backbone-0.9.9

[#425] Fix Dataset.query() when called with Query model