WIP: Hotfix/ubuntu1404 compatibility
Fixes minor build warnings/errors associated with switching to Ubuntu 14.04 due to the newer version of gcc.
Updated files:
- cmake/modules/FindXenomai.cmake (updated to suppress unused_local_typedefs warnings when building libbarrett)
- include/barrett/systems/inverse_dynamics.h (updated to fix an error due to the gcc 4.7 upgrade when building libbarrett/sandbox)