Tests are revised for AdjMat though they are still failing.

The problem with the current test is the metric for adjacency. Former adjacency
metric relied on Python's interpretation of ints as booleans (0 False, everything
else True). However, our "disconnected" state is represented by -1.

TODO: Can Adjacency matrix represent acyclic graphs? This is at the root of our
problem!
A couple of notes.