Read a wind marker file

In case one needs a wind source (like a ventilator) the feature has to be switched in the Parameterfile and a wind marker file has to be specified in the initial-files section. The wind-file provides the code basically the location and direction of wind sources, i.e. a constant velocity will be given to the gas at the wind marker positions. The wind direction is specified by the following numbers: 2 the +x direction, 3 the -x direction, 4 the +y direction,5 the -y direction, 6 the +z direction and 7 the -z direction.