Log Message:
tex-schulmathematik{,-doc}: update to 1.6

package schulma: new command \Rechenkaestchen

document class schulma-ab: avoid doubling page numbers when
using the twoside option

document class schulma-klausur: new class option MusterloesungD;
bug fix concerning the xcolor package; avoid doubling page numbers
when using the twoside option

document class schulma-komp: new commands \Nr and \Klausurdatum,
automatic title generation; hide competence list when using the
Musterloesung class option