New features

• Reworked rejuvenation spell 
  •  Rejuvenation now heals gradually over a specified amount of time instead of all at once.
• Added levels 11 to 20

Balance notes

• Adjusted level 10 waves
• Increased spell max level from 3 to 5
• Buffed Warg level 3 HP
• Buffed Boar level 3 HP
• Buffed Bear HP (all levels)
• Removed unit cost increase when leveling up