Makes helmet icon south state consistent with east/west states

Made security helmet south sprite consistent with the east/west ones. The side view shows the sides of the helmet coming down towards the back of the head, not up. Now the front view agrees with this.

![helmet2](https://cloud.githubusercontent.com/assets/242428/5023491/7e2fc2ea-6ac7-11e4-9646-ce00656feec9.png)

Also adds tajaran and unathi sprite sheets for the tactical helmet and balaclavas. The shape of the standard ones left no room for a muzzle, and so the sprite appeared to clip into the player's face.

![cat](https://cloud.githubusercontent.com/assets/242428/5024002/eef9af28-6ad0-11e4-85a7-192128ec6e2f.png)

These new sprites don't really cover the face as much, but I guess it's a lot better than clipping.