Add projectiles #58
Description
Add projectiles which are shootable by the player. The projectiles should be child-friendly. Examples:
- Bow and arrows
- Gun which uses something funny to shoot with, such as potatoes.
There should be a projectile class which is derived from either the object or entity class. Important members of the class are:
- z_velocity (gravitation)
- forward_velocity (The speed in which the projectile accelerates within)