Refactor physical unit support
Refactor physical unit support

tomhughes/carto,madeinqc/carto,CartoDB/carto,mapbox/carto,whitelynx/carto,gravitystorm/carto,clhenrick/carto,1ec5/carto,midnightcomm/carto,stefanklug/carto,CartoDB/carto,pnorman/carto