look for metadata only in head of page
make xpath more restrictive, add .head for getting metatags
Merge pull request #720 from adam3smith/em-header

look for metadata only in head of page
[Atypon] Make export form xpath more flexible
[ACS] Decode URI when retrieving DOI
[AIP] Make sure we have the correct date
Note that, while BibTeX and ENW have the correct year, their data is generally much worse (e.g. only year, some messed up page ranges, etc.)
Closes #721
Thanks @robamler
[EM] Add a few more Google meta tags
See http://www.monperrus.net/martin/accurate+bibliographic+metadata+and+google+scholar#Survey for a nice list with samples
[RIS] Some tweaks to work better with REFMAN
Re https://forums.zotero.org/discussion/36083/export-from-refman-to-zotero-without-losing-special-characters/
Fix a bug with zField handling
Separate "extra" content with newlines instead of semicolons
[CiteSeer] Stricter detectWeb filtering
[Wiley] Don't break on institutional authors
[EM] Fix invalid xpath when title contains double quote
add translator for medium.com
Add translator for SSOAR

* uses the BibTeX export and call BibTeX translator
* add/correct language, book series and number
Merge pull request #722 from zuphilip/master

Add translator for SSOAR
adds basic dataset support to CrossRef. closes https://github.com/zotero/translators/issues/723
push CrossRef timestamp. (argh timestamps!)
test updates: AIP, Cell, IBIS, Ingetna, Isitore, Medium;
Fix to CanLII and biblio.com after minor site redesigns;
Small fix to finding importable multiples on frontiers;
Improve detectWeb precision for Atypon
Delete 3 unused functions (experiments with identifier parsing)
Merge pull request #725 from zuphilip/master

Delete 3 unused functions (experiments with identifier parsing)
[RSC] Temporary (I hope) workaround for meta tags in body