Wave spawner reworked

Hi!

I just have finished rewriting wave module. It was the oldest part of the code in my game, and during development process it became, well, unefficient. New mechanism allows me to quickly create, adjust, or expand new and existing waves as new prefabs. New script allows me to choose enemy type (or types, randomly picked up), rotation and position.


Enemies chosen as random can be easily multiplied and fixed in one place (because default setting for random enemies randomizes their spawn position).

I have also adapted all existing waves to new system and created a copule of new waves. New system also forces me to recreate a campaign mode, but I have almost finished this task. Moreover - this system allows me to simply add users custom waves and campaigns created in .xml format.

I am also working at abilities cooldown system.