Bugfix in model.py
Bugfix in model.py

Fixes:
  File "/home/rmgpy/source/rmg/model.py", line 876, in simulate
    logging.info('At t = %s, an edge species flux exceeds the critical flux for simulation interruption' % (solver.t, maxSpecies))
TypeError: not all arguments converted during string formatting

nyee/RMG-Py,faribas/RMG-Py,chatelak/RMG-Py,pierrelb/RMG-Py,chatelak/RMG-Py,faribas/RMG-Py,nyee/RMG-Py,KEHANG/RMG-Py,enochd/RMG-Py,comocheng/RMG-Py,comocheng/RMG-Py,enochd/RMG-Py,nickvandewiele/RMG-Py,KEHANG/RMG-Py,nickvandewiele/RMG-Py,pierrelb/RMG-Py