Enhanced the test of ElementalMapping:

I added a small stack (256x256x4) that is used at the test class.
The test automatically determines the correct path to the images.
Tried to implement the MultiDimFit for correctSREELS:

I can read the date for files and store them into a matrix.
But the fit fails with the following error message:
Exception in thread "main" lma.LMAMatrix$InvertException: Matrix is
singular.
Inversion failed for matrix: ...