remove trialgenerator.py
remove trialgenerator.py

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