WIP: Working with zipped gadm2 id-iso concordance file
Adding gadm2.zip to resources
GADM version 2 data now available via gadm2->iso
Added gadm2 to static-datasets map
Merge pull request #361 from reddmetrics/feature/gadm2-zip

fully incorporated gadm2 data with gadm2->iso function and helpers
Remove OS X metadata files from gadm2.zip
Merge pull request #364 from reddmetrics/feature/fix-gadm2-zip

Remove OS X metadata files from gadm2.zip
Fixed merge conflict