Glow manipulation

I did a couple more things to the graphics engine to allow the glow to be turned on and off for certain objects. Namely, I made it so the pods only glow when they're in use. I also had to tweak my custom shader code because the normals weren't showing up correctly. The models were being drawn flat with no shadows. I figured out that this was because the actual normals of the ship weren't being used - just a normal map. What's supposed to happen is the normal map is used like a filter through which the actual normals of the models get passed. Without the actual normals, the normal map doesn't do anything.

I also tweaked the targeting mechanism so that not only does it consider distance of the enemy when deciding which enemy to lock onto, but also the angle between it's relative position to the player ship and the player ship's forward direction (in other words, how close is it to the player's targeting reticle).