[WIP] change(postproc): datatypes for mothers & daughters in picker

WHY IS THIS CHANGE NEEDED?:
- tuple is dangerous because immutable

WHAT SIDE EFFECTS DOES THIS CHANGE HAVE?:
- yet to see

EVIDENCE THAT COMMIT WORKS:
- yet to see

REFERENCES:
- issue #37

src/postprocessor/core/reshapers/picker.py

@@ -102,8 +102,8 @@ class picker(LineageProcess):
             self.daughters = np.array([])
         else:
             self.mothers, self.daughters = (
-                tuple(self.cells.mothers_daughters[:, 1]),
-                tuple(self.cells.mothers_daughters[:, 2]),
+                list(self.cells.mothers_daughters[:, 1]),
+                list(self.cells.mothers_daughters[:, 2]),
             )
         for alg, op, *params in self.sequence:
             if indices: