Sumonetvis

This release features two new features for OBJ export:

* Optional generation of a flat planar "terrain" mesh within a given buffer distance of network objects
* Ability to map default material names to user-defined ones via the material_mapping parameter

See full documentation and README for more information.

Contains the following fixes:
* Face normals in OBJ export are now properly oriented
* Catch exceptions when invalid or unexpected geometry is generated by the shapely parallel_offset function
* Allow passing of "color" kwarg to all plotting functions

Fix API breakage due to circular import.

This release brings a number of improvements, including support for the following objects:

* Additional files
* Bus stops
* Polygons
* POIs (plotting only, no OBJ export)
* Crosswalks
* Stop lines

as well as substantial under-the-hood refactoring and improvements to provide slightly better performance and more flexibility for future expansion. In addition, a bug resulting in an Exception when reading a network file which contains edges with custom <param> elements was resolved, as is often the case with converted OSM data.

This release fixes a bug that occurs when a line offset results in an empty geometry. It also enables more customization via support for matplotlib plotting function kwargs (such as transparency, for example).

This release adds the ability to export a Wavefront-OBJ file.