updated usage of sbml input with stdin
updated usage of sbml input with stdin

stanleygu/sbml2matlab,luciansmith/sbml2matlab,luciansmith/sbml2matlab,luciansmith/sbml2matlab,hsauro/sbml2matlab,stanleygu/sbml2matlab,stanleygu/sbml2matlab,hsauro/sbml2matlab,hsauro/sbml2matlab,stanleygu/sbml2matlab,luciansmith/sbml2matlab,hsauro/sbml2matlab,stanleygu/sbml2matlab,luciansmith/sbml2matlab,hsauro/sbml2matlab