nanshe/imp/segment.py: Make sure all values in `properties` are ordinary strings or NumPy will have issues. Fixes jakirkham/nanshe#243.
nanshe/imp/segment.py: Make sure all values in `properties` are ordinary strings or NumPy will have issues. Fixes jakirkham/nanshe#243.

jakirkham/nanshe,DudLab/nanshe,nanshe-org/nanshe,nanshe-org/nanshe,DudLab/nanshe,jakirkham/nanshe