Give Object instances that represent "datasets" the ability to be queried

[davecap]

It can be confusing that Objects are also Datasets but they don't have the same helper functions (like "query()". If an Object is a type "dataset", it should be possible to at least query it. How can we blend the Dataset class into the Object class?

One way is to have different sub-classes for each Object type, like DatasetObject, FileObject, FolderObject. Or we can deprecate the Dataset class itself and replace it with a subclass of Object (called Dataset), and add File and Folder subclasses.

[jsh2134]

in #315 I added a pass-through for query() so now you can do Object.retrieve(dataset_id).query(**)

however there are still 10+ other methods that are on the Dataset object that may be wanted (dataset.beacon(), dataset.activity() etc...)

[davecap]

What about adding a __getattr__ and returning the result of getattr(Dataset, "attr") if the object type is dataset? We can limit the list of valid attrs to "beacon, activity, etc.." if we want.