Discover tests in classes called FooTest as well as TestFoo.

We have we have classes called, for example, OutputTest, OutputUnitTest, ArkaneTestThermo,
 CommonTest, InputTest, Psi4LogTest, QChemLogTest, TeraChemLogTest, ArkaneGaussianLogTest,
 MolproLogTest, OrcaTest, ArkaneTest, ArkaneKineticsTest, FluxDiagramTest, SimulateTest,
 DiffModelsTest, GenerateReactionsTest, CanteraTest, RMGToCanteraTest, MergeModelsTest,
 regressionTest, IsotopesTest, ReactionSystemTest, to name just a few...

They were being ignored by pytest. 
Maybe we should rename them, but for now lets reconfigure pytest.

pytest.ini

@@ -24,3 +24,4 @@ addopts =
     --cov-report html
 testpaths = test
 python_files = *Test.py
+python_classes = *Test Test*