add socket activation for extensions (#118)

Option `X-AW-Socket` is used. Any message received by this socket will
trigger extension update. If the option is set, `X-AW-Interval` will be
ignored

sources/awesomewidgets/extquotes.h

@@ -55,12 +55,14 @@ public slots:
 
 private slots:
     void quotesReplyReceived(QNetworkReply *reply);
+    void sendRequest();
 
 private:
     QNetworkAccessManager *m_manager = nullptr;
     QUrl m_url;
     bool m_isRunning = false;
     Ui::ExtQuotes *ui = nullptr;
+    bool canRun() const;
     void initUrl();
     void translate();
     // properties