Metronome and Stopwatch User Interface

New Timer window in UI for Metronome (Ableton Link management) and replaces Timers. Former Timers in Metrics are replaced with Runtime (of session, of program and of total vimix runtime in settings). Temporarily disconnected Metronome from MediaPlayer actions.

MediaPlayer.h

@@ -188,6 +188,10 @@ public:
      * Seek to zero
      * */
     void rewind(bool force = false);
+    /**
+     * pending
+     * */
+    bool pending() const { return pending_; }
     /**
      * Get position time
      * */
@@ -296,11 +300,14 @@ private:
     GstVideoInfo v_frame_video_info_;
     std::atomic<bool> opened_;
     std::atomic<bool> failed_;
+    bool force_update_;
+    bool pending_;
     bool seeking_;
     bool enabled_;
     bool rewind_on_disable_;
     bool force_software_decoding_;
     std::string decoder_name_;
+    bool metro_linked_;
 
     // fps counter
     struct TimeCounter {
@@ -348,8 +355,9 @@ private:
 
     // gst pipeline control
     void execute_open();
+    void execute_play_command(bool on);
     void execute_loop_command();
-    void execute_seek_command(GstClockTime target = GST_CLOCK_TIME_NONE);
+    void execute_seek_command(GstClockTime target = GST_CLOCK_TIME_NONE, bool force = false);
 
     // gst frame filling
     void init_texture(guint index);