Crosslet Package not Working

问题

https://github.com/ramnathv/rMaps

I tried reproducing this example and the map isn't showing:

 library(rMaps)
crosslet(
  x = "country", 
  y = c("web_index", "universal_access", "impact_empowerment", "freedom_openness"),
  data = web_index
)

Do I not have a package that will allow this to happen. I have installed the following:

rCharts
rMaps
jsonlite

来源：https://stackoverflow.com/questions/32830566/crosslet-package-not-working