add articulation spec to skeleton plugin device descriptor
add articulation spec to skeleton plugin device descriptor

godbyk/OSVR-Core,OSVR/OSVR-Core,OSVR/OSVR-Core,OSVR/OSVR-Core,OSVR/OSVR-Core,godbyk/OSVR-Core,OSVR/OSVR-Core,godbyk/OSVR-Core,OSVR/OSVR-Core,godbyk/OSVR-Core,godbyk/OSVR-Core,godbyk/OSVR-Core