Remove more wxT() macros from samples

Also use wxString instead of wxChar* strings.

Closes https://github.com/wxWidgets/wxWidgets/pull/950

samples/ipc/client.cpp

@@ -251,7 +251,7 @@ void MyFrame::OnStart(wxCommandEvent& WXUNUSED(event))
     m_client = new MyClient;
     bool retval = m_client->Connect(hostname, servername, topic);
 
-    wxLogMessage(wxT("Client host=\"%s\" port=\"%s\" topic=\"%s\" %s"),
+    wxLogMessage("Client host=\"%s\" port=\"%s\" topic=\"%s\" %s",
         hostname.c_str(), servername.c_str(), topic.c_str(),
         retval ? "connected" : "failed to connect");