Plopter wip

Hey, 
All of the things I modified should be restricted to the /Tools/autotest directory. Except for the 
"
// TODO(BrandonJ): Uncomment this on next commit
// stabilize_plane();
" 
lines. 

To run the sim as it stands, got to /Tools/autotest and run 
"./sim_vehicle.sh -w -v ArduCopter -f Rascucopter --console --map"

The input coming in is pwm = [1000, 2000]. I subtract by 1080 because 1070 is the ESC arm PWM value and shouldn't produce a thrust. The 0.1 is a fudge factor I was using to debug. It will be gone on the next iteration.

You're right though. A mapping of (pwm[i]-1070)/930.0 is probably more appropriate. I'll change to that.