Collecting Assertions

[emjun]

Right now, collecting and formatting assertions from properties of variables and effects sets is blended together into one step (see Tisane.collect_assertions and helper methods)

Seems to me that the right/better design would be:
collect assertions -> dict [in Tisane class where going to be controlling modeling?]
format assertions -> can pick ASP vs. SMT (hypothetically) although we are focusing on ASP [helper method]
query with assertions -> knowledge base [KnowledgeBase is just a wrapper around the ASP solving process]

Pro:

• makes code more modular and therefore more extensible
  Con:
• more work to do 😛
• update, add new tests

Related Issues: Issue #9, #13