Compile SubobjectClassifier( FinQuivers ) to a fixed value

[mohamed-barakat]

We need to compile SubobjectClassifier( FinQuivers ) to its value, e.g., simply by evaluating it. We expect this to have a significant impact on other commands like ListOfSubobjects, PushoutComplement, DPO, etc.

[mohamed-barakat]

We also need to compile (again, e.g., by evaluation)

TruthMorphismOfTrueToSieveFunctorAndEmbedding( UnderlyingCategory( FinQuivers ) )

(see #83). This is necessary for the precompilation of PushoutComplement, DPO, etc.