Cover the special case that are no search parameters present

* VuFind/Search/Solr/Params.php (getQuery): Cover the special case
  that are no search request parameters present.
Set spelling dictionaries based on configuration

* VuFind/Search/Factory/AbstractSolrBackendFactory.php
  (createBackend): Set spelling dictionaries based on configuration.
Comment out settings that are used in backend factory

* VuFind/Search/Solr/Options.php (init): Comment out settings that are
  used in backend factory.
Only use sort parameter if sort order is set in Params

* VuFind/Search/Solr/Results.php (createBackendParameters): Only
  use sort parameter if sort order is set in Params.
Implement spellcheck

* VuFind/Search/Solr/Results.php (createSpellingQuery): New function. Create spellcheck query.
  (createBackendParameters): Use new function, save the spelling query
  for later processing.
  (processSpelling): Rewritten. Use Spellcheck from search response.
  (getSpellingSuggestions): Retrieve saved spelling query.
  ($spellingQuery): New propery. Spelling query.
Merge branch 'search-refactor' of ssh://vufind.git.sourceforge.net/gitroot/vufind/vufind into search-refactor