Fix construction of a MCFrame from MCFrames
Fix construction of a MCFrame from MCFrames

Resolves #307

tkoolen/drake,thientu/drake,tkoolen/drake,edowson/drake,hanssusilo/drake,scottviteri/drake,hanssusilo/drake,sheim/drake,hanssusilo/drake,psiorx/drake,sheim/drake,manuelli/drake,edowson/drake,edowson/drake,edowson/drake,tkoolen/drake,psiorx/drake,tkoolen/drake,crogers3/drake,sheim/drake,hanssusilo/drake,manuelli/drake,scottviteri/drake,manuelli/drake,edowson/drake,thientu/drake,thientu/drake,astrorog/drake,psiorx/drake,crogers3/drake,hanssusilo/drake,billhoffman/drake,tkoolen/drake,billhoffman/drake,thientu/drake,tkoolen/drake,billhoffman/drake,hanssusilo/drake,manuelli/drake,billhoffman/drake,astrorog/drake,scottviteri/drake,crogers3/drake,crogers3/drake,crogers3/drake,sheim/drake,billhoffman/drake,thientu/drake,scottviteri/drake,astrorog/drake,astrorog/drake,crogers3/drake,astrorog/drake,sheim/drake,crogers3/drake,edowson/drake,astrorog/drake,sheim/drake,billhoffman/drake,scottviteri/drake,edowson/drake,sheim/drake,psiorx/drake,psiorx/drake,crogers3/drake,thientu/drake,psiorx/drake,psiorx/drake,sheim/drake,manuelli/drake,billhoffman/drake,scottviteri/drake,thientu/drake,scottviteri/drake,manuelli/drake,edowson/drake,hanssusilo/drake,astrorog/drake,billhoffman/drake,tkoolen/drake,psiorx/drake,hanssusilo/drake,manuelli/drake