Removed need for spinor and clover stride constants -  now members of DslashParam and PackParam structs.  Fixed bug when calling commDim in dslash_pack.cu.  Multi-GPU dslash should now work (not yet fully tested).
Staggered dslash test defaults to improved staggered (QUDA_ASQTAD_DSLASH), instead of incorrectly defaulting to Wilson.