Multi-year Budget View

[nowthis]

This probably needs another input screen entirely, but much of the same underlying JavaScript.

• Take as input a spreadsheet listing multiple years of a budget.
• Produce a separate Sankey diagram for each year's budget, holding the scale constant so that the same amount across years appears to be the same height.
• Provide plenty of options for customizing colors, etc.
• Produce each graph as a separate item, so they can be arranged as the user wishes
• 3 potential modes -- all the income sources, all the expenses, or both.
• For bonus points:
  • To make small-multiples more practical, support leaving out labels from each graph and producing a Legend instead
  • Keep track of the inflation multiplier so that years can be compared in constant dollars