GenericFluid and GenericNetwork now create a 'pore.map' and 'throat.map' property.  I *think* this was causes problems with map_pores and map_throats in cases where physics or geometries had not been defined everywhere.
Trim now works when Phase and/or physics objects are present
empty pore.map and throat.map are now created in the init...so if no pores or throats are sent the map_pores/throats will still work.