jsonalchemy: dumps with specified keywords

* Adds an option to dump only specified keys from dictionary.

Signed-off-by: Leonardo Rossi <leonardo.r@cern.ch>
Reviewed-by: Jiri Kuncar <jiri.kuncar@cern.ch>
search: fix filtered output format

* Addresses issue with research and export that not accept the "ot"
  filter argument.  (closes #2292)

Signed-off-by: Leonardo Rossi <leonardo.r@cern.ch>
Reviewed-by: Jiri Kuncar <jiri.kuncar@cern.ch>