add ltl2ba interface
add ltl2ba interface

based on PLY and returning a BA with symbolic edge guards.
tulip-control/tulip-control,necozay/tulip-control,necozay/tulip-control,necozay/tulip-control,tulip-control/tulip-control,tulip-control/tulip-control,tulip-control/tulip-control,necozay/tulip-control,necozay/tulip-control