applyExtFunction expects x, y and z

[vincentvanhees]

Function applyExtFunction expects object data with only x, y and z column, but with the recent changes in release 3.0-6 it is also given a timestamp column.

As we discussed it would be good to allow for providing time column, but it seems that the existing code cannot handle this.
Therefore, for the time being, I am going to insert data = data[, c("x", "y", "z")] to prevent problems when running external function such as step detection.