AA: Add a rudimentary aa::Pass <-> Andersen interface.
AA: Factor out push/pop in Andersen.
AA: Implement some very basic IR -> constraint conversion.
AA: Bootstrap the worklist in Andersen::solve().
AA: Fix constraint generation in Andersen.
AA: Solve the three basic constraints in Andersen (ref, deref, store).
AA: TODO -- need to create AMLs & constraints for heap allocs.