eliminate signed/unsigned warning
eliminate signed/unsigned warning

elen4/simbody,Gjacquenot/simbody,simbody/simbody,elkingtonmcb/simbody,chrisdembia/simbody,elkingtonmcb/simbody,simbody/simbody,elen4/simbody,scamille/simbody,elkingtonmcb/simbody,Gjacquenot/simbody,robojukie/simbody,chrisdembia/simbody,chrisdembia/simbody,robojukie/simbody,robojukie/simbody,scamille/simbody,Gjacquenot/simbody,scamille/simbody