support long in slicing
support long in slicing

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