Changed code to separate graph stacking logic by axis.
Merge branch 'CSG/MultiAxis-StackedGraph' into CSG-v1.0.1
Adding test for multi axis stacking
Merge branch 'CSG/MultiAxis-StackedGraph' into CSG-v1.0.1
Merge pull request #313 from CSGOpenSource/CSG-v1.0.1

Stack series per axis