get rid of signed/unsigned warning
get rid of signed/unsigned warning

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