QuadPilot v0.4

This version includes the latest deveopement of the Rpi controller as well as the Remote App.

News :

- Start and Stop PID from remote
- Shutdown Rpi from Remote, no need to ssh into the Rpi
- PID on all three axis has been tested and validated

Stabilized PID control

Exit PID loop + bug fixes

First working version of quad_pilot.