Mandatory gunner & allow duplicates

After using this tool with 2 of my friends for a week we came to 2 conclusions: when there was no gunner in our team of 3 the mission inevitably went to shit, and also we thought it might be funky to play with a few duplicate classes sometimes, even though that might be sub-optimal. So i added those 2 options to the menu. No clue what else might be needed but i guess y'all can suggest what you want to see implemented in the comments.