Support multiple file globbing.
Support multiple file globbing.

dask/dask,mrocklin/dask,pombredanne/dask,dask/dask,mraspaud/dask,blaze/dask,ContinuumIO/dask,pombredanne/dask,mikegraham/dask,jcrist/dask,jakirkham/dask,gameduell/dask,blaze/dask,cowlicks/dask,ContinuumIO/dask,vikhyat/dask,chrisbarber/dask,jcrist/dask,PhE/dask,cpcloud/dask,mrocklin/dask,PhE/dask,jakirkham/dask,mraspaud/dask,vikhyat/dask