Add heartbeat receiving to scheduler
Add heartbeat receiving to scheduler

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