Treemaps in Plotly

[phidesigner]

Would be nice to see Plotly support for Treemaps e.g. Treemapify.

Warning messages:

2: In geom2trace.default(dots[[1L]][[1L]], dots[[2L]][[1L]], dots[[3L]][[1L]]) :
geom_GeomTreemap() has yet to be implemented in plotly.

[cpsievert]

Added to #566, but we may be able to do treemaps via ggraph plugins cc @thomasp85

[thomasp85]

Indeed