Add get_registered_workers func to client
Add get_registered_workers func to client

blaze/dask,pombredanne/dask,ssanderson/dask,dask/dask,simudream/dask,pombredanne/dask,jayhetee/dask,wiso/dask,ContinuumIO/dask,wiso/dask,clarkfitzg/dask,mraspaud/dask,PhE/dask,vikhyat/dask,jcrist/dask,PhE/dask,ssanderson/dask,simudream/dask,chrisbarber/dask,vikhyat/dask,ContinuumIO/dask,mrocklin/dask,clarkfitzg/dask,mrocklin/dask,mraspaud/dask,freeman-lab/dask,cowlicks/dask,jakirkham/dask,gameduell/dask,jakirkham/dask,cpcloud/dask,blaze/dask,mikegraham/dask,jcrist/dask,freeman-lab/dask,dask/dask,jayhetee/dask