Merge branch '52-questions-on-symmetrizingoperator' into 'NIFTy_5'

Resolve "Questions on SymmetrizingOperator"

Closes #52

See merge request ift/nifty-dev!105

nifty5/operators/symmetrizing_operator.py

@@ -42,4 +42,5 @@ class SymmetrizingOperator(EndomorphicOperator):
             lead = (slice(None),)*i
             v, loc = dobj.ensure_not_distributed(v, (i,))
             loc[lead+(slice(1, None),)] -= loc[lead+(slice(None, 0, -1),)]
+            loc /= 2
         return Field(self.target, dobj.ensure_default_distributed(v))