Addressing @DavAug comments on emcee hammer bug fix
Addressing @DavAug comments on emcee hammer bug fix

- corrects and expands docstrings in emcee hammer
- separates out function for selecting another index
- used for informative variable names

addresses #1325

martinjrobins/hobo,martinjrobins/hobo,martinjrobins/hobo,martinjrobins/hobo