Test script

[chrishavlin]

Need to some testing functionality to make sure we don't break anything as we're re-organizing the code.

#14 does the bulk of the work for this, but we still need at least a test function for the bayesian_inversion function.

[chrishavlin]

#15 now includes a test for bayesian_inversion on a lower resolution grid. We'll still want to re-run the high-res test before paper submission and code archiving, but I think we're good to just run the low res tests as we're finishing the other issues in #2