Reduce precision requirement for elliptical model IRF computation to 1e-2.
Initial implementation of elliptical model kernels fur stacked cube analysis, and relax precision requirement for binned elliptical model to 1e-2.
Rename from test_binned_ml_fitting.py to test_ml_fitting.py.
Add additional test datasets.
Add elliptical model support.
Adapt script for elliptical model testing.