Fixed spawning bug, added endless mode, and tuned balancing

Goblin Hero v0.1

General

• Added a second game mode, Endless, where you try to survive for as long as possible instead of being bound to 5 minutes maximum
• Minor balancing tweaks

Balancing

Sword

• Increased base damagefrom 5 to 8
• Increased damage upgrade from 15% to 20%
• Increased attack speed upgrade from 10% to 20%
• Lowered attack speed upgrade cap from 5 to 4

Bat enemy

• Lowered HP to 20 from 30

Bugs

• Fixed a bug where enemies would occasionally spawn outside of the playable arena
  
• Fixed a bug in the meta upgrade screen where the next cost would still display after you have maxed out an upgrade