Geochron

- Add ability to specify opacity in timehex_timestampedgeojson

- Change default color scheme to be the min and max of a time period rather than all data in timehex_timestampedgeojson

Adds helpers for pydeck visualizations and adds proper weighting for geosynchnets.

Features:
Supports data formats useful for Folium visualizations
Changes:

Package distribution bug fix

- Add geo synchronous networks as a supported data structure
- Make dependencies truly optional

Initial release