MSTIS uses new MSOuter object (but same input)
MSTIS uses new MSOuter object (but same input)

Only changes are internal; but that's an important step before
changing the inputs.

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