Calculate ETE and Fuel in Realtime

[der-On]

The server needs to send current fuel of aircraft to make fuel calculations work.
On each cycle the left flight time and left fuel consumption should be calculated and display somewhere on the interface.

[der-On]

On each aircraft poll we need to calculate ETE and Fuel to the first next waypoint (first in waypoints list) and the totals. We also need to check if the aircraft is within a minimal distance to the first next waypoint. If so the first next waypoint can be removed or set as "passed" and the the next waypoint will become the waypoint to calculate ETE and Fuel to.