Add some links to README.
Add some links to README.

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