Creates dendrogram plot using ggplot.

### Demonstrate ggdendrogram

library(ggplot2)
hc <- hclust(dist(USArrests), "ave")

# Demonstrate plotting directly from object class hclust
p <- ggdendrogram(hc, rotate=FALSE)
print(p)

ggdendrogram(hc, rotate=TRUE)

# demonstrate converting hclust to dendro using dendro_data first
hcdata <- dendro_data(hc)
ggdendrogram(hcdata, rotate=TRUE, size=2) + labs(title="Dendrogram in ggplot2")