Consume algorithm and ConsumeThing ctor should be the same

[relu91]

While constructing an Exposed Thing or a Consume Thing, the TD used is never been validated. Is this intentional?

As discussed in today's call, it seems that it is inconsistent to have a validation step only in the consume method and not inside the constructor of the ConsumeThing object. We should reconcile the factory method and constructor. On a possible solution, it might be moving the consume algorithm inside the ConsumeThing constructor. Then just call the constructor in the consume method. However, we may lose the ability to asynchronously initialize a ConsumedThing, therefore we might still discuss here the pros and cons.

Derived from #239