Testing refine methods

[johnomotani]

There are now several methods for refining points: line, newton, integrate, integrate+newton.
Only line is tested in test_equilbrium.py, and using other methods sometimes fails where line passes. I suspect this is because the tests start with points very far from the contour, and were set up in such a way that line would find the right contour, so this does not indicate a problem with the other methods. The failure of integrate may just be a question of slightly too tight tolerance (only fails test_refine), and integrate+newton fails to converge, but only on the same test. newton fails to converge on several tests.

[bendudson]

This is tricky... there are cases when any (or all?) of these methods may fail. Newton in particular is either great or terrible depending on how close to the solution you start. We could use a simple test case where they all should pass, but a proper test (rather than a sanity check) is probably hard to design.