Stacked BarChart Interactivity

[EmmanuelDodoo]

          Some features to consider adding to this model:

• Interactive reordering of the sections either on a bar basis or globally
• Hovering effects for more details?
• Toggling on/off particular categories
• Support for both positive and negative stacked bars
• Filtering out either positive and negative stacked bars

Originally posted by @EmmanuelDodoo in #20 (comment)