Get clustering Rmds from Luc

[angela-li]

We need to ask Luc for the raw versions (Rmds) of the following tutorials, so we can update and enhance them for the last part of the tutorials:

• Cluster Analysis (1), PCA - live, html on Github
• Cluster Analysis (2), Classic Clustering - live, html on Github
• Cluster Analysis (3), Spatially Constrained Clustering - live, html on Github

[angela-li]

Email sent to Luc with request!

[angela-li]

Uploaded in 1e22af9.

Luc's note: "More than the other sections, these are a work in progress and there is some new functionality that will be inserted later this spring."