WFS: reference offset is not correctly applied for calculating WFS reference point

[mgeier]

The reference offset has to be applied in the local coordinate system of the reference position and orientation.

Currently, it seems to be applied in the global coordinate system.

This means that the WFS signals are wrong in the presence of a reference rotation and a reference offset position (at the same time).

Since normally, the reference position/rotation is zero, we haven't noticed that when we were experimenting with the BoomRoom many years ago, but I guess the error was already there ...