Fix bug and add 2 features

Fixes issues with editors and translator fields described in http://forums.zotero.org/discussion/22795/wikipedia-citation-templates-fails-to-export-editors-of-book-sections/

Separates page numbers with an en-dash as per wikipedia Manual of Style.

Automatically adds pmid,pmc and jstor fields from data in the extra field and url.

See http://en.wikipedia.org/wiki/Help_talk:Citation_Style_1#Zotero_wikipedia_export_improvements for wikipedia editor comments.