Makes jetpacks more obvious when they're on

Previously jetpacks were annoyingly hard to see if they're on or off because you have to see whether a 2-pixel animation is looping or not on a tiny sprite. Now, if they're red, they're off, if they're green, they're on. They are still animated, but it's less hard to see out of the corner of your eye whether the jetpack is on or not.

![off](https://cloud.githubusercontent.com/assets/7247232/5551532/7b50e690-8b87-11e4-8631-5e06a1724937.png) ![on1](https://cloud.githubusercontent.com/assets/7247232/5551533/7c2f9fa2-8b87-11e4-828d-a1742e1c922c.gif)

![off2](https://cloud.githubusercontent.com/assets/7247232/5551536/7e854dba-8b87-11e4-9247-848851076be6.gif) ![on2](https://cloud.githubusercontent.com/assets/7247232/5551537/84558da4-8b87-11e4-81b6-66f9050204ad.gif)


Additionally, I have added a message for when you toggle the jetpack on/off. Hopefully nuke ops won't leave their jetpacks on all round now.