search404 7.x-1.2-alpha1

#1253426: Patch: Search 404 should use default search engine by yareckon: Changed the logic for selection of the search engine to be used to use the settings from admin search settings; Added support for ds_search which returns its own search array
#1253426: Patch: Search 404 should use default search engine by yareckon: Modified to use the default search set by the user in the admin search settings page
#1546370: Search404 page shows no results and no search field when site uses ApacheSOLR by marktfrey, victoriachan: Fixed issue with generation of apache_solr search form when auto search is disabled
#1467982: no results when using apachesolr beta 16 by drasgardian: Fixed issue with search results being put into a variable inside the results array by apache solr in the search_data call
#1353188: The Apache Solr search engine is not available by paulmckibben: Fixed issue with redirection to search results when apache_solr is used as the search engine
#1076190: Search API integration (patch) by Blackice2999: Added support for Search API integration through redirection to a custom path
#1306364: Google CSE search only works when auto search is enabled by byrond: Fixed issue with Google CSE not being set as the search engine when go to results is not enabled