HUD fixes

-Enemy health bar thinner
-Enemy Health bar appears when within set distance
-Player and Companion portraits placeholders set
New AI Behaviors

2 new Behavior Script variations:

Enemy_Melee_Behavior
-doesn't fire bullets
-Approaches players until adjacent
-does a little jump and does damage when in range (melee)
-Has default +50% (150) targeting range

Enemy_Large_Behavior
-behaves like a normal shooter, but spawns
-has a setable spawn timer, default 400 frames(?)
-instantiates the prefab set to the spawnPrefab var in the air next to
them
-only instantiates if the player and companion aren't right next to it.