Dev/rosenblatttransform (#241)

- added rosenblatttransform 
- added 3x3 eta methods 
- interpolation can be used with various eta functions
- added documentation for interpolation, eta calculation 
- exposed full eta struct in python 
- disable ClusterFinder for 2x2 clusters 
- factory function for ClusterVector

---------

Co-authored-by: Dhanya Thattil <dhanya.thattil@psi.ch>
Co-authored-by: Erik Fröjdh <erik.frojdh@psi.ch>

python/CMakeLists.txt

@@ -31,7 +31,7 @@ set( PYTHON_FILES
     aare/CtbRawFile.py
     aare/ClusterFinder.py
     aare/ClusterVector.py
-
+    aare/Cluster.py
     aare/calibration.py
     aare/func.py
     aare/RawFile.py