Enhanced algorithms to calculate board connections:
    Previously, a track was seen connected to a pad only if the track end is
    exactly on the pad position.
    Now a track is seen connected to a pad if the track end is inside the pad shape.
    Algorithm to calculate pads connections to track is still very fast.
    However some other functions (drag pads, track len calculation ...)
    still need the track end exactly on the pad position.
Dead code removal.