Waypoint Setup Routine Added and a bunch of other changes

1. fixed the fail_safe so it works correctly. the pro-mini will not change a state until the signal is at a steady state condition (~.100s). also, the fail_safe will always state the car in MANUAL mode until the TX is turned on.
2. added function to bypass the menu system and start a waypoint setup routine. this is activated by holding down ch3. the routine will bypass the menu system, start the gyro, and then will wait UNTIL the ch3 button is at MANUAL. at that point, it'll continue on and then allow setting up waypoints.
3. how the car finishes was updated. it will now continue on in a straight line when the max number of waypoints is reached OR if (0,0) is reach. (end_run function was moved from the navigation.cpp file and incorporated into the main loop...probably a better location for it.)