media nodes: moved video/audioinput category to media base

They both have the same category, so they can share the same code in their base.

app/node/input/media/audio/audio.cpp

@@ -19,11 +19,6 @@ QString AudioInput::id() const
   return QStringLiteral("org.olivevideoeditor.Olive.audioinput");
 }
 
-QString AudioInput::Category() const
-{
-  return tr("Input");
-}
-
 QString AudioInput::Description() const
 {
   return tr("Import an audio footage stream.");

app/node/input/media/audio/audio.h

@@ -12,7 +12,6 @@ public:
 
   virtual QString Name() const override;
   virtual QString id() const override;
-  virtual QString Category() const override;
   virtual QString Description() const override;
 
 private:

app/node/input/media/media.cpp

@@ -32,6 +32,11 @@ MediaInput::MediaInput() :
   AddInput(footage_input_);
 }
 
+QString MediaInput::Category() const
+{
+  return tr("Input");
+}
+
 StreamPtr MediaInput::footage()
 {
   return footage_input_->get_standard_value().value<StreamPtr>();

app/node/input/media/media.h

@@ -33,6 +33,8 @@ class MediaInput : public Node
 public:
   MediaInput();
 
+  virtual QString Category() const override;
+
   StreamPtr footage();
   void SetFootage(StreamPtr f);
 

app/node/input/media/video/video.cpp

@@ -30,11 +30,6 @@ QString VideoInput::id() const
   return QStringLiteral("org.olivevideoeditor.Olive.videoinput");
 }
 
-QString VideoInput::Category() const
-{
-  return tr("Input");
-}
-
 QString VideoInput::Description() const
 {
   return tr("Import a video footage stream.");

app/node/input/media/video/video.h

@@ -15,7 +15,6 @@ public:
 
   virtual QString Name() const override;
   virtual QString id() const override;
-  virtual QString Category() const override;
   virtual QString Description() const override;
 
   NodeInput* matrix_input() const;