Add info in Readme.md about compiling lesson

[jebyrnes]

For those of us who want to modify and check how things work, can you add info to the readme.md - even just a link - on how to test compilation on our own computers. Some of us are old hands at individual markdown documents, but lack experience in this larger workflow.

Hrm. Oughta be a DC lesson on that....or some pages? (been looking around, but haven't found it)

[jsta]

Nice idea, in the mean-time the necessary system setup is described here and the build process starts by running make serve in a terminal and viewing your localhost in a browser.

[jsta]

Looks like this info is in the README at https://github.com/datacarpentry/r-raster-vector-geospatial and could be ported over.