Add translator for zbMATH (http://www.zbmath.org/) aka Zentralblatt Mathematik

* calls BibTeX translator
* correct some tiny mistakes
* add some additional information
fix special character issue in bibtex
Merge pull request #689 from adam3smith/bibtex

fix special character issue in bibtex
add Hoovers and IBISWorld Business reports
Merge pull request #684 from zuphilip/master

Add translator for zbMATH (http://www.zbmath.org/) aka Zentralblatt Mathematik
add io-port
fix citekey description in bibtex
add field 773 for journal articles&chapters to MARC. This works best for HLAS http://hlasopac.loc.gov/webvoy.htm
only tested basic functionality on other sites; it's also relatively rare
Changed Factiva translator, based on the webpage

* there seems to be no XML-export from Factiva and before the translator was based on this XML-export
* now the translator identifies the information directly on the webpage(s)
* Handles Frame Option well as No-Frame Option (with monitorDOMChanges)
* handles different display options
* add stable url, snapshot
* add normalization of date
Merge pull request #690 from zuphilip/master

Changed Factiva translator, based on the webpage