Fix floor and future division in io.py
Fix floor and future division in io.py

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