dendro_plot: Make a clean dendrogram plot
In zhuchcn/zheatmap: Heatmap With Dendrograms

This function takes a dendrogram and make plot using the ggdendrogram function. The returned plot is a ggplot object

This function should be only called from internal

1	dendro_plot(dend, rotate = FALSE, x.expand)

`dend`	a dendrograme, generated by dendrogram_basic function.
`rotate`	logic value. If true, the output plot will be rotated 90 degree clockwise. Useful to make row wise dendrogram
`x.expand`	numeric. The x expand value. This value is used to make sure the width of the dendrogram is exactly the same as the heatmap.