AreaChart : new props (xAxisValueFormatter and legendMapper)

[flodef]

Hi team,

In the AreaChart, it could be fantastic to have this 2 props :

• xAxisValueFormatter: like the currentValueFormatter but for the XAxis. For example, I have some date for the xAxis and I would like to display them in a specific format
• legendMapper : map a column to a legend. For example, my data has fields called A,B,C. I don't want to change my data structure, but I would like to display my fields as Field 1, Field 2 and Field 3

Thanks