geoschem/gcpy: GCPy 0.1.0

This is the first labeled version of GCPy. The primary functionality of GCPy is plotting and tabling diagnostics from GEOS-Chem. Main features include: Functions for comparing GEOS-Chem benchmark output for multiple versions of GEOS-Chem, including 2D plots and mass and budget table creation. Support for plotting benchmark output for both GEOS-Chem Classic (lat/lon data) and GCHP (cubed-sphere data). The first official release version of GCPy, v1.0.0, will correspond with the release of GEOS-Chem 13.0.0