Memoisation

The underlying R code in the Docker images uses the memoise package to cache certain function calls to a folder in the working directory called degauss_cache. This can be safely deleted after running any container, but if kept and the docker image is called again from the directory containing the cache directory, it will use the cached results rather than redownloading shapefiles or geocoding again. This can be especially useful when one of many counties fails to download and the entire container process fails. In this case, running the command again will not require redownloading/recomputation of items that have previously been completed. Because of the support for multithreaded geocoding using the CB::cb_apply function, the cache folder for geocoding is called cache instead of degauss_cache.