add bib file import

[WolfgangFahl]

given a bib file as input lookup and optionally create data records for wikidata:

• paper
• proceedings
• author
• event
• eventseries

[WolfgangFahl]

Example input: https://jens-lehmann.org/files/cv.bib

Intermediate output:

('DBLP:conf/www/AuerDLR07', Entry('inproceedings',
      fields=[
        ('title', 'OntoWiki: A Tool for Social, Semantic Collaboration'), 
        ('url', 'http://ceur-ws.org/Vol-273/paper_91.pdf https://jens-lehmann.org/files/2007/ontowiki.pdf'), 
        ('year', '2007'), 
        ('date', '2007-01-01'), 
        ('booktitle', 'Proceedings of the Workshop on Social and Collaborative Construction of Structured Knowledge (CKC 2007) at the 16th International World Wide Web Conference (WWW2007) Banff, Canada, May 8, 2007'), 
        ('volume', '273'), 
        ('publisher', 'CEUR-WS.org'), 
        ('series', 'CEUR Workshop Proceedings'), 
        ('keywords', ''), 
        ('pubstate', 'published'), 
        ('tppubtype', 'inproceedings')],
      persons=OrderedCaseInsensitiveDict([('author', [Person('Auer, S\\"{o}ren'), Person('Dietzold, Sebastian'), Person('Lehmann, Jens'), Person('Riechert, Thomas')])]))),