Added crystals/power up spawning.

Cyan crystal = Primary fire plasma blaster (fast fire rate, average projectile speed).

Purple crystal = Primary fire void lance (average fire rate, fast projectile speed).

Green crystal = Secondary fire Ion mortar (average fire rate, average projectile speed, lobbed shot).

Orange crystal = Secondary fire heat ray (average charge delay, continuous beam attack).

Blue crystal = Shield (can take an extra hit).