Add automated tests to the Matlab API

[tbleher]

Since Matlab is the reference implementation, it is crucial that it is correct. There should therefore be automated tests that can be run on CI. I propose using https://github.com/MOxUnit/MOxUnit (a MIT licensed unit test framework for Matlab/Octave) for this.

This would also make it possible to check which parts of the code work correctly with Octave.

Plus, having good tests would make it easier to create a Python API (or port parts of the code to Python) and be sure that the new code has identical behavior to the original Matlab code.

[CarawaySeed42]

Having a Matlab Testsuite could also be used to make sure that the Matlab and C-API return the same results for functions that they both implement.
As an example this could be realized using a wrapper function using the Matlab C-API which calls the respective CRG C-API functions.
-> Call evaluation function of the CRG Matlab API, call corresponding C-API function using wrapper function, compare results