The two bugs of Feb 16 2009 (reading SBML models) are fixed

The previously found bugs have been fixed. The corrected code (in
mod/modiSBML.c) is available in the official CVS repository at
http://savannah.gnu.org/projects/mcsim

The new code correctly reads in multiple parameter declaration sections
and assign stoichiometry of 1 by default to species references in reaction
sections.