added kwarg to opt out cache clearing
added kwarg to opt out cache clearing

wesbarnett/pymbar,wesbarnett/pymbar,kyleabeauchamp/pymbar,Lnaden/pymbar,kyleabeauchamp/pymbar,wesbarnett/pymbar,kyleabeauchamp/pymbar,mrshirts/pymbar,mrshirts/pymbar,Lnaden/pymbar,jchodera/pymbar,choderalab/pymbar,Lnaden/pymbar,choderalab/pymbar,kyleabeauchamp/pymbar,choderalab/pymbar,wesbarnett/pymbar,mrshirts/pymbar,jchodera/pymbar,jchodera/pymbar,mrshirts/pymbar,jchodera/pymbar