Added verbosity flag. Various other small cleanups.

Hi Felix,

Good to be back hacking. I added this verbosity stuff because I don't feel like the Javascript is doing the right thing. Now when you run "./godrone-util -verbose=1 run" you'll see a new line for every change in firmware.Desired. Then when you use the keys in the UI, you'll see some strange behavior, like Yaw going up on the first keypress back down, etc.

(Also, Yaw can go to negative 400, which seems unlikely to be right. Will attack that some other time.)