Partial fix to persistent issue with LPN to SBML translator.  General fix needs to deal with fact that places becoming unmarked can still disable transitions.
Partial fix to persistent issue with LPN to SBML translator.  General fix needs to deal with fact that places becoming unmarked can still disable transitions.

MyersResearchGroup/iBioSim,MyersResearchGroup/iBioSim,MyersResearchGroup/iBioSim