Reactivate ellow, ellup as optional input parameters
Christoph asked about the ellow, elup input parameters. At the moment these are still available as optional parameters in the input schema definition, but it looks like they are never read in. He indicated that experts might want to use them to cut off the lowest energy eigenvalues to investigate the difference of the treatment of semicore states as core states or with LOs as valence states without changing the LAPW basis.
If it doesn't hurt we should reactivate these parameters but keep them optional so that they are only ever seen and known by experts.