remove unneeded imports
remove unneeded imports

dwhswenson/openpathsampling,openpathsampling/openpathsampling,openpathsampling/openpathsampling,choderalab/openpathsampling,choderalab/openpathsampling,choderalab/openpathsampling,openpathsampling/openpathsampling,openpathsampling/openpathsampling,dwhswenson/openpathsampling,dwhswenson/openpathsampling,dwhswenson/openpathsampling