rewrite load_file for jtlv to return strategy as networkx.DiGraph
rewrite load_file for jtlv to return strategy as networkx.DiGraph

and let the conversion to a machine happen at a single place: synth.strategy2mealy
This simplifies the jtlv interface, reduces complexity and code duplication.
necozay/tulip-control,necozay/tulip-control,tulip-control/tulip-control,tulip-control/tulip-control,necozay/tulip-control,tulip-control/tulip-control,necozay/tulip-control,necozay/tulip-control,tulip-control/tulip-control