Balance updates, fixes and quality of life changes!

Changelog:

• Start game in full-screen by default (on first run)
• Repair pickups spawn slightly more often
• Cobra ship starts with Bomb-bot in Novice mode (instead of Repair-bot)
• Bomb-bot now only triggers at 1 health remaining
• Repair-bot triggers at end of level, rather than beginning of level
• Buff 3-way weapon
• New Difficulty (Rank) graph to show dynamic difficulty
• Fix upgraded Flamer motion at level higher than 1
• Fix [REDACTED]'s final attack blocking some shots unintentionally