Print output to debug the TestEvalModel unit test

This unit test is failing on Travis only on Python 3.6 but not Python 3.5 on PR #20,
and we can't make sense of why. This is mostly a "no change" pull request to trigger 
the CI tests, but I added a print(output) statement to help debug.

pyteck/tests/test_eval_model.py

@@ -219,6 +219,7 @@ def test(self):
                 num_threads=1,
                 skip_validation=True
                 )
+            print(output)
             assert numpy.isclose(output['average error function'], 58.78211242028232, rtol=1.e-3)
             assert numpy.isclose(output['error function standard deviation'], 0.0, rtol=1.e-3)
             assert numpy.isclose(output['average deviation function'], 7.635983785416241, rtol=1.e-3)