Changed takeoff detection implementation

- takeoff is detected with a jumper seen that can connect a digital
input (with internall pullup resistors enabled) to ground. The jumper is
initially plugged in, and the digital input value is LOW. When taking
off, the jumper is manually removed, and the digital value is HIGH.
Added pins definitions for cameras on/off control and servo
Fixed a bug in flight phase transition code

- switchToNextFlightPhase() was never called ;-)
Fixed a bug in flight phase 0 camera processing

- added a delay to ensure that cameras are turn off properly before
turning them on again
Changed flight phase pause and duration constants