Fix dshape constructor to accept unicode in python 2
Fix dshape constructor to accept unicode in python 2

ContinuumIO/datashape,FrancescAlted/datashape,markflorisson/datashape,FrancescAlted/datashape,cpcloud/datashape,aterrel/datashape,ContinuumIO/datashape,blaze/datashape,llllllllll/datashape,blaze/datashape,aterrel/datashape,markflorisson/datashape,quantopian/datashape,cpcloud/datashape,quantopian/datashape,cowlicks/datashape,cowlicks/datashape,llllllllll/datashape