Add fixtures for SOLR 4.x error response json/arrarr
Merge branch 'master' of ssh://vufind.git.sourceforge.net/gitroot/vufind/vufind
Merge branch 'master' of ssh://vufind.git.sourceforge.net/gitroot/vufind/vufind
Refactor SOLR V4 ErrorListener

* VuFind/Search/Solr/V4/ErrorListener.php
  (getResponseBodyMediaType): New function. Return normalized
  response body media type identifier.
  (analyzeJsonErrorResponse): New function. Analyze response body
  and return appropriate tags.
  (onSearchError): Refactored. Use new functions.
Add abstract base class of SOLR error listeners

* VuFind/Search/Solr/V3/ErrorListener.php: Extend
  AbstractErrorListener.
* VuFind/Search/Solr/V4/ErrorListener.php: Extend
  AbstractErrorListener.
* VuFind/Search/Solr/AbstractErrorListener.php: New
  class. Abstract base class of error listeners.