refs #290 using a CRange of iterator adaptors in implementating the tertiary predicate-based methods of the derived containers,

but preserving the return-by-copy for API stability

src/blackmisc/nwtextmessagelist.cpp

@@ -123,7 +123,7 @@ namespace BlackMisc
          */
         CTextMessageList CTextMessageList::findByFrequency(const CFrequency &frequency) const
         {
-            return CTextMessageList(this->findBy(&CTextMessage::getFrequency, frequency));
+            return this->findBy(&CTextMessage::getFrequency, frequency);
         }
 
         /*