rename budget to label_size, add to docstrings
rename budget to label_size, add to docstrings

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