Change on/off to true/false in runcards

Created by: voisey

Apparently on/off are no longer acceptable values for booleans as far as the parser is concerned, but it seems a lot of runcards haven't been updated to reflect this. I noticed because I tried to run a fit (based on a 3.1 runcard) where I switched on to off and I got unexpected results. So far I've just updated the files in nnpdfcpp/config.