- HiddenFiles are now created in the same room as the Viewer
- implemented drop support from containers to Viewer (thanks to Patrick)

TODO: get Object with real room of object ( = do not steal PDFs; idea in mind)
Merge branch 'develop' of https://github.com/winfel/wa_knowledge_structuring into develop

Conflicts:
	source/objects/2.Viewer/view.js

removed different solution from Patrick (sorry!)