v2.1.0

Main changes :

• The OSM loader has been rewritten. It now uses a fast C++-based PBF reader dedicated to extract a routing graph
• New plugin for (multimodal) isochrones
• Better packaging of Python packages: pytempus and tempusloader
• Experimental support for Tempus as a PostgreSQL extension: wps_tempus.isochrone(), see sql/pgtempus
• Various bug fixes