Patch 0.67c: shop fixes and other improvements

[h3]Puropu Defense Squad 0.67c IS LIVE!

PATCH NOTES:[/h3]

• [FIXED] Shops would sometimes misbehave in multiplayer
  
• [FIXED] Host player would sometimes be able to buy upgrades for free
  
• Optimizations on various visual effects
  

Keep the bug reports and requests coming through the in-game form, or on our Discord and Steam forums! ːsteamhappyː