Add minimum distance data

[svmiller]

I know I've done this before for other analyses. I just have to gulp write a script that will make that data, let it do its thing for a few hours, and have that as a raw data source on hand for a quickie function.

[svmiller]

I reminded myself: I did write the script to produce the data, just not a function to add them. They're in the package as gw_mindist and cow_mindist. I'll just need to write a function for them.

[svmiller]

Added, in pilot form. Closing for now.