Added basic Enemy Capsule Pace holder called Default_Enemy and gave it a new Solid Black Material. Also created a blank C# script for it called Enemy.cs. Gave it a Prefab in a folder under /Resources/Prefabs/Enemies/
Altered Bullets so they are actually destroyed after 5 seconds. Gave bullets a rigid body so that they could detect triggers and made the enemy collider a trigger. Put code into enemy.cs so that it has health and is destroyed when it reaches 0. Also gave a method to decrease health from the enemy.

Gave Bullet.cs a damage variable defaulted to 1 and made it call the take_damage method whenever it encounters an enemy (OnTriggerEnter) then destroy itself. Gave Enemy a tag called Enemy.
Closed Unity in order to finish feature
Merge branch 'feature/Making_a_Simple_Enemy' into develop