Adds security segways

Adds security segways, including leaving them in the Security area of Box.

The code is very close to the Janicart, with various modifications and tweaks. Most notably:
-The segway can now be damaged by beams... it is fragile, and can only take about five shots before being destroyed. No more reflections!
-You can't travel in space anymore. Sorry, only drifting through the void contemplating your final moments now.
-It provides slip protection against water, but NOT lube... The user will fall off and drop the key if they drive over it

It also could use a new sprite for the key, and I'd like to add a faster version with less health and no slip protection, but let's see how this goes down.