Better WaveData parsing
Differentiate trickle and burst waves.

Trickle: Continuous flow of enemies into level. Enemies can continue to
respawn after being destroyed.

Burst: Sudden burst of enemies into level during a short period of time.
Enemies will not respawn when destroyed.
Add wave spawn position randomization.

Burst seems ok, trickle needs work.
Need to add logic for avoiding spawn directly into black hole.