Port over the ORSO and bayes benchmark tests from the MATLAB

[StephenNneji]

Port the ORSO unit test and data in tests/ORSO folder and the bayes benchmark example

[alexhroom]

The ORSO unit tests seem to directly test the abelesSingle routine, which is in the compiled code, so isn't actually testing anything specific to the MATLAB... should we leave the ORSO test for the Python, or should the Python test the ORSO data 'from the top', i.e. from calculating a RAT Project with the ORSO layer data?