open CORE results in a new tab
Merge pull request #132 from OAButton/features/131-core-newframe

open CORE results in a new tab
Improve CrossRef lookup

Use the application/vnd.citationstyles.csl+json format instead of
application/json, as it's easier to parse and more reliable
Merge pull request #65 from OAButton/improve-crossref-lookup

Improve CrossRef lookup