Ensure stochastic equivalence expansion (mostly) does not genreate equivalences of much larger depth.
This stops the case where we generate a very large or infinite number of equivalences.
Fix broken constructor calls in stochastic search.
Bugfix: Properly set result string for newly-expanded expressions during stochastic search.
Stochastic search improvements.
Added a new model that stores the probabilities of different types of expressions (e.g., calls, +).
Weigh method probabilities by how useful their return type is (toward those that satisfy the type constraint and away from those we've seen before).
Avoid generating lots of unlikely equivalent expressions.