[Therion] unselect in thconfig

[Stefan Oswald]

Hi together, 

We have a problem exporting multiple .pdf files from different maps of one cave. It should work like this in thconfig: 

source zusammenbau

  select map1 at zusammenbau
  export map -o m1.pdf
 unselect m1 at zusammenbau

 select map2 at zusammenbau
  export map -o m2.pdf
 unselect m2 at zusammenbau

With only the map1 at zusammenbau ->m1.pdf is generated correctly; as soon as we add the second select-export-unselect in both .pdf files both maps are drawn.