added base for SPSS export
PSPP screenshots for documentation
diverse improvements...
added ctrl/alt modifier to open saved file in default app/skip save dialog
added typ enumber and some flexibility to fieldname_list and pdf_document
added typ enumber and documented even two more...
added decorator to check which modifiers are being pressed
Merge branch 'develop' into deco
added Tech-Dok.pdf to git-repo (and README.md)