Get dates for nodes in synthetic tree from chronograms in phylesystem
See ReadTheDocs for the API, a work in progress. Currently the main dependency is on python-opentree, which is used here to return the OpenTree singleton.
Configuration settings described in default.config. Copy to "~/.chronosynth/config.ini" st set local config or 'CHRONOSYNTH_CONFIG_FILE' in environment, or it will use the values forn defaul.config.