Update ggplot-heatmap.R so that column names follow the dendrogram and heatmap

Previously, the column names (leaves on the dendrogram) were not plotted with their respective branches created by hierarchical clustering. Instead, they were displayed in their original input order.

I changed labels=colnames(x) to labels=colnames(xx) in col.plot in ggheatmap function and the order of "##order of dendros" wrt "##dendro plots".

Thank you for sharing this script, it was very helpful!