Minor translation issues in core

* someones eagle eye recognised these two minor errors in core translation files

bibtex-export

* removes field 'crossref' from bibtex-export
* crossref is used for links to records (host items) within the same bibtex file, not to link to the record itself. See https://en.wikipedia.org/wiki/BibTeX#Cross-referencing for examples
* if used, the field causes trouble with literature management software who interpret it as link to host item

fixed typo in resolverLinks templates

- Some CSS adjustments to jquerymobile to match.

* refactored signature of OpenUrl->isActive()
* updated tests to new signatures in OpenUrl view helper
* updated templates to new signatures in OpenUrl view helper
* corrected 'records' location to 'record' for consistency with config.ini.

- Moved more logic into OpenUrl view helper.
- Added configuration to control display of OpenURLs without code changes.
- Renamed OpenURL record driver methods for improved consistency.
- Added tests.

Wording definitions from parent themes will be inherited
or overwritten respecting the theme inheritance hierarchy.

- Added support for restricted Solr result sets.
- Based on work in pull request #414.

p.lead to h2

- Resolves VUFIND-1125