Fix compilation errors found by Travis.
Fix compilation errors found by Travis.

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