MadgraphControl change: Clean gridpack, correct generate_from_gridpack
Add feature to Madgraphcontrol described in https://its.cern.ch/jira/browse/AGENE-1656 to clean partially the NLO gridpacks, based on the work done by @fgiuli . Also corrected small bug preventing to generate events from gridpacks in the nightly of 21.6.30
Edited by Louis Helary