Fix boost atomic linking
Fix boost atomic linking

Optionally look for and link atomic library. This should satisfy the
dependency when thread was built against atomic but also allow us to
link against non-atomic enabled versions.

frizaro/Veloview,Kitware/VeloView,Kitware/VeloView,frizaro/Veloview,frizaro/Veloview,Kitware/VeloView,frizaro/Veloview,Kitware/VeloView,Kitware/VeloView