merged video and audio nodes into a single media node

They performed exactly the same function so I don't think we need the clutter.

Also bumped the project version, but old projects are automatically converted.

app/widget/viewer/footageviewer.cpp

@@ -32,10 +32,10 @@ FootageViewerWidget::FootageViewerWidget(QWidget *parent) :
   ViewerWidget(parent),
   footage_(nullptr)
 {
-  video_node_ = new VideoInput();
+  video_node_ = new MediaInput();
   sequence_.AddNode(video_node_);
 
-  audio_node_ = new AudioInput();
+  audio_node_ = new MediaInput();
   sequence_.AddNode(audio_node_);
 
   connect(display_widget(), &ViewerDisplayWidget::DragStarted, this, &FootageViewerWidget::StartFootageDrag);

app/widget/viewer/footageviewer.h

@@ -21,8 +21,7 @@
 #ifndef FOOTAGEVIEWERWIDGET_H
 #define FOOTAGEVIEWERWIDGET_H
 
-#include "node/input/media/audio/audio.h"
-#include "node/input/media/video/video.h"
+#include "node/input/media/media.h"
 #include "node/output/viewer/viewer.h"
 #include "viewer.h"
 
@@ -49,9 +48,9 @@ private:
 
   Sequence sequence_;
 
-  VideoInput* video_node_;
+  MediaInput* video_node_;
 
-  AudioInput* audio_node_;
+  MediaInput* audio_node_;
 
   QHash<Footage*, int64_t> cached_timestamps_;