Towards Populating Stage 1-6 Enemies

Multi-part enemies, and basic behaviours for the stage 1 midboss and boss have now been implemented. This should serve as a base from which to build out placeholder enemies for all six stages. Over the next week or two the plan is to build out prototype enemies:

turrets and tanks

zako (basic flying enemy)

heavy enemies

midbosses and bosses

This may involve a little extra work implementing and tweaking extra systems as needed, eg changes/additions to the enemy shot or movement systems