Adds a plasma storage HUD for aliens.

After about four hours of headaches at trying to learn hud code, this was made.  It shows the alien's current amount of plasma on the left side of the screen.  It looks like the changeling and the blob's counters and was based off of it.

Only issue is that it will be blank until plasma is gained or lost but that's a minor thing.

Loads of thanks to Cheridan as well as anyone else on coderbus who helped since I am dumb.

Screenshot: http://i.imgur.com/Ood71E5.png