Elsevier: fixing problems and adds running "harvest" from local
files.
Merge branch 'master' of https://github.com/kaplun/scoap3

Conflicts:
	elsevier_package.py
Elsevier, OUP: copyright extraction

* Fixes copyrights extraction from papers.
JATS, NLM, A++ fixes for creation dates.
OUP, NLM: fixes download from OUP and extracts arXiv ids.

* Looks for go.xml file that was missing in the file_list.
* Adds arXiv id to the record.
* Adds arXiv id to the references (added also for JATS).
Introducing new script to generate list of DOIs
Sorting journals in alphabetical order
Improving nations.py