switch arXiv back to journalTitles. Grab data from CrossRef for publishe...

...d article. 
addresses https://github.com/zotero/translators/issues/616
@karnesky - if you could have a quick look at the tests at the end of the translator to see if the data looks sensible to you, that'd be great.
I'm now grabbing the article data for published articles from CrossRef