small fix to n2to3 for mhd parameter read, update to BB test

git-svn-id: https://svn.mcs.anl.gov/repos/nek5/trunk/tools@1016 24248562-e74d-0410-ab4b-d4d80c744c73
fix import of bad elements in VTK / VTX import in build.f

git-svn-id: https://svn.mcs.anl.gov/repos/nek5/trunk/tools@1017 24248562-e74d-0410-ab4b-d4d80c744c73