add predefined html colors to Graphics.Plotly.Base.Color

[stites]

This would include all of these colors and probably belongs in Graphics.Plotly.Color.Predefined.

On a related note, I'm not sure how much support you want to put into the colors in plotly since it seems like you could get a lot of functionality for free if you just depend on something like JuicyPixel, friday, colors, or colour.