Some subtle gameplay tweaks

• SKULLBOY and SENTINEL shouldn't generate fire trails
  
• Reduce SENTINEL recharge value so they regain less health
  
• Stop level generator from carving islands
  
• Stop PINK THUGS from reflecting bullets when spawning from crates
  
• Inversely scale "Dragon Breath" when player fire rate is buffed
  
• Skip "Burning Bullets" glitch if player is struggling (low timeouts) or level too high
  
• Made GOLEM bullets more subtle to match cherub bullets