Merge pull request #55 from mnfienen/classy

fixed a couple minor bugs in refactoring of getfield method
working on mean elev and slope properties for each elevation method (for input into accumulate_same_levelpathID)
premerge
Merge remote-tracking branch 'upstream/classy' into classy
Updated the CELLS classes to include reading in the centroid of each river cell. This will allow confirmation of routing by using the distance from segment starting and ending locations and their proximity to one another. In the process of this, I had to use a da.SearchCursor to populate the CELLS properties in the first place. --> note, still need to finish the routing, but this is an incremental commit (plane is about to land anyway).