previewer: template fixes

Signed-off-by: Adrian-Tudor Panescu <adrian.tudor.panescu@cern.ch>
Reviewed-by: Jiri Kuncar <jiri.kuncar@cern.ch>
base: PDFTK path discovery

Signed-off-by: Adrian-Tudor Panescu <adrian.tudor.panescu@cern.ch>
Reviewed-by: Jiri Kuncar <jiri.kuncar@cern.ch>
jsonalchemy: JSON-LD tweaks

* Adds "inline" synonim for "full" export format to comply with
  specification.

* Fixes __meta_metadata__ cleanup at JSON-LD export time.

Signed-off-by: Adrian-Tudor Panescu <adrian.tudor.panescu@cern.ch>
Reviewed-by: Jiri Kuncar <jiri.kuncar@cern.ch>