previewer: zip previewer enhancements
- Identifies folder by id of the tree elment. (closes #2748)
- Adds fullscreen mode.
- Expands all elements by default. (closes zenodo/zenodo#157)
Signed-off-by: Adrian Pawel Baran <adrian.pawel.baran@cern.ch>
Reviewed-by: Jiri Kuncar <jiri.kuncar@cern.ch>