pipe_drivers provides some useful scripts for processing data on a cluster using ctrl_pool. I propose it be bundled with lsst_distrib so users can use it conveniently.
pipe_drivers will also pull in ctrl_pool and therefore mpich and mpi4py. mpi4py had some
trouble building on OSX recently, but this has been resolved. Based on recent lsstsw runs, pipe_drivers builds fine and should not break lsst_distrib when included.