ENH: Allow more flexibility with geometries
Changeup tests to reflect drop=False default
Only define name 'geometry' in one place
Allow setting of crs in set_geometry
ENH: Add set_dataframe method to DataFrame
CLN: crs set order: passed in, passed Series, DataFrame.
Merge pull request #60 from jtratner/be-flexible-with-geometry-column

Allow arbitrary geo col name and add set_geometry method to DataFrame