Update Comparison tests to Catlab > v0.16.9

[lukem12345]

Comparison tests in test/ModelComparison.jl pass on Catlab v0.16.9 but fail on later versions.

I am not sure what the intention of these tests is, but note that by changing line 32 in test/ModelComparison.jl from

so = Subobject.(legs(c_res))

to

so = Subobject.(feet(c_res))

, all following logical tests pass save for:

¬(A ∧ B) != ¬(A) ∨ B

and

implies((A∧B), A) == A∨B

Those tests further pass if == and != are substituted in respectively.

[kris-brown]

I'll look into this! Seems caused by AlgebraicJulia/Catlab.jl#909