Don't create folders with \ in log module

Also don't try to write files with ? in filename

Fix #377

modules/log.cpp

@@ -84,7 +84,7 @@ void CLogMod::PutLog(const CString& sLine, const CString& sWindow /*= "Status"*/
 
 	// $WINDOW has to be handled last, since it can contain %
 	sPath.Replace("$NETWORK", (m_pNetwork ? m_pNetwork->GetName() : "znc"));
-	sPath.Replace("$WINDOW", sWindow.Replace_n("/", "?"));
+	sPath.Replace("$WINDOW", sWindow.Replace_n("/", "-").Replace_n("\\", "-"));
 	sPath.Replace("$USER", (m_pUser ? m_pUser->GetUserName() : "UNKNOWN"));
 
 	// Check if it's allowed to write in this specific path