Fixed a huge late game lag spike issue! Few balance changes!

There was an issue which caused huge lag spike in the later game when enemies died near turrets, this was fixed with a much more optimized way of finding new targets for the turrets.

Some balance changes:

• More enemies
• Enemies handicap grows exponentially now instead of cubically
• Rocket launcher cost increased, but it is also more powerful now
• The starting nexus now has 4 starting laser turrets on top
• Weapon upgrades only increase weapon damage by 10% (25%->10%)
• Armory size shrinked from 3x3x5 -> 3x3x2