Ref T259, Ref T243 client provider used with network classes

Also adds a dummy testing class

src/blackmisc/network/clientprovider.h

@@ -105,9 +105,17 @@ namespace BlackMisc
             CClientAware() {}
 
             //! Constructor
-            CClientAware(IClientProvider *clientProvider) : m_clientProvider(clientProvider) { Q_ASSERT(clientProvider); }
+            CClientAware(IClientProvider *clientProvider) : m_clientProvider(clientProvider) { }
             IClientProvider *m_clientProvider = nullptr; //!< access to object
         };
+
+        //! Client provider dummy for testing
+        class BLACKMISC_EXPORT CClientProviderDummy: public IClientProvider
+        {
+        public:
+            //! Dummy instance
+            static CClientProviderDummy *instance();
+        };
     } // namespace
 } // namespace