diamonds shiny example

[cpsievert]

From @MySchizoBuddy in #583

The shiny-plotly example about diamonds facet plots has an input slider named height of plot which doesn't do anything. The server.R code doesn't use it anywhere. Either remove that slider or show us how to change the plot height using the slider

Also pageWithSidebar() is deprecated you have to use fluidPage instead

[royr2]

Have updated example and app...