Patch 0.3.1

Hello! This is just a small post-update patch to fix a crash I overlooked. I've also included a few other small tweaks and updates.

• Stability
  • Fixed a crash that could occur at higher danger levels when moving to a new area
  • Added object pooling to damage numbers to improve performance
• Gameplay
  • After clearing an area, all XP is now collected before leaving
  • Increased initial projectile spread angle for Wyvern and Defender turrets
• Audio
  • Added new Troop Transport soldier voice pack