BibEdit: import CrossRef data

* Adds BibEdit input field for DOI on record/edit page.
* Adds module crossrefutils which gets XML from
  CrossRef page and transforms it into MARCXML.
* Adds crossref2marcxml.xsl to translate XML from CrossRef
  into MARCXML.
* Adds function to normalize author name. Removes spaces
  between initials.

Reviewed-by: Javier Martin Montull <javier.martin.montull@cern.ch>