normix: implement unit test

[hechth]

We need a unit test for the normix function to see how the parameter estimation is actually implemented.

This function takes an EIC and should return the peak parameters for all peaks in the EIC.
The peaks are already identified and the retention time values of the peaks are passed in the pks variable.
The valleys which separate the peaks are also passed in the vlys variable.

The schmematic below shows how the test data can be simulated:

So then the parameters can be checked since mu should be close to the peak positions and mu values used to generate the data (same for the standard deviations) and the scale parameter is the a variable used to scale the testing data.