Make symmetrisation of vetoes automatic in LauVetoes for symmetric DPs - but add new allowed indices (4 and 5) to allow vetoes to be applied to mMin or mMax if desired

git-svn-id: svn+ssh://phab.hepforge.org/source/laurasvn/trunk@431 30227d83-a2f9-49e9-9e98-657c83b2c86a