Effect Set: Change to include Concepts, rather than Concept names?

[emjun]

As of Jan. 5, 2021, the Effect Set uses strings of Concept names (due to how we generate effects from the conceptual graph, and ultimately how we create nodes in the concept graph).

To make it easier/facilitate more seamless modeling from Effect Set (see model function in Tisane class), it may make more sense to use concepts, rather than strings?

[emjun]

Pro Concepts rather than just Concept names:

• if we use Concepts, the interface for generating the constraints is consistent, less error-prone since we can rely on Concepts to give their Variable names or, in the case of no data, their names. With only Concept names in Effect Set, we can't rely on/use this feature.

As of Jan. 11: The ASP constraint generation code hacks around the fact that Effect Sets provide only Concept Names (strs). This code will not cover edge cases where the variable names (in the dataset) are different from the concept names.