Made sure FilterEngine instances are always initialized

include/AdblockPlus/FilterEngine.h

Index: include/AdblockPlus/FilterEngine.h
===================================================================
--- a/include/AdblockPlus/FilterEngine.h
+++ b/include/AdblockPlus/FilterEngine.h
@@ -63,25 +63,27 @@ namespace AdblockPlus
 
   typedef std::tr1::shared_ptr<Filter> FilterPtr;
   typedef std::tr1::shared_ptr<Subscription> SubscriptionPtr;
 
   class FilterEngine
   {
   public:
     explicit FilterEngine(JsEnginePtr jsEngine);
-    bool IsInitialized() const;
     FilterPtr GetFilter(const std::string& text);
     SubscriptionPtr GetSubscription(const std::string& url);
     std::vector<FilterPtr> GetListedFilters() const;
     std::vector<SubscriptionPtr> GetListedSubscriptions() const;
     std::vector<SubscriptionPtr> FetchAvailableSubscriptions() const;
     FilterPtr Matches(const std::string& url,
         const std::string& contentType,
         const std::string& documentUrl);
     std::vector<std::string> GetElementHidingSelectors(const std::string& domain) const;
 
   private:
     JsEnginePtr jsEngine;
+    bool initialized;
+
+    void InitDone();
   };
 }
 
 #endif