Bug fix for IDWLapseLocalAlgorithm: a global detrend of the station data was...

Bug fix for IDWLapseLocalAlgorithm: a global detrend of the station data was performed before doing the local interpolation, followed by a global retrend afterwards. This doesn't seem to be consistent with the local interpolation, which should detrend/retrend only on the local scale.

Also adding the option MAXD to be able to specify the maximum allowed distance between stations and the grid point to interpolate to. I have a use case for it, so others may have too!