Update of powheg scripts so to be able to use both LHAPDF 5 and 6

Example output LHE file of the updates is here:/afs/cern.ch/work/s/syu/public/LHE/cmsgrid_final.lhe
The updates include the following:

1) Add example cards that use new CT10 (11000) or NNPDF3.0 (260000) PDF sets.
2) create_powheg_tarball.sh is back to what Roberto puts in originally
 in runcmsgrid.sh
3) runcmsgrid.sh includes weights variations include 100 NNPDF3.0 errors, 52+1 CT10 PDF, 16 CT10 alphas variations, central value of MSTW2008 NLO 68 CL, NNPDF 2.3 central value and two alphas variations.