Deprecate Searcher creation.

As the `Searcher` is now deprecated, we also remove the unit tests on it.
`Searcher` is now untested, and so it reduces the code coverage.

include/searcher.h

@@ -56,6 +56,8 @@ struct SuggestionInternal;
 /**
  * The Searcher class is reponsible to do different kind of search using the
  * fulltext index.
+ *
+ * The Searcher is now deprecated. Use libzim search feature.
  */
 class Searcher
 {
@@ -63,7 +65,7 @@ class Searcher
   /**
    * The default constructor.
    */
-  Searcher();
+  DEPRECATED Searcher();
 
   ~Searcher();