Isolate implementation of CloneSource

Source.h

@@ -328,37 +328,6 @@ protected:
 };
 
 
-class CloneSource : public Source
-{
-    friend class Source;
-
-public:
-    ~CloneSource();
-
-    // implementation of source API
-    void setActive (bool on) override;
-    bool playing () const override { return true; }
-    void play (bool) override {}
-    bool playable () const  override { return false; }
-    void replay () override {}
-    uint texture() const override;
-    bool failed() const override  { return origin_ == nullptr; }
-    void accept (Visitor& v) override;
-
-    CloneSource *clone(uint64_t id = 0) override;
-    inline void detach() { origin_ = nullptr; }
-    inline Source *origin() const { return origin_; }
-
-    glm::ivec2 icon() const override;
-    std::string info() const override;
-
-protected:
-    // only Source class can create new CloneSource via clone();
-    CloneSource(Source *origin, uint64_t id = 0);
-
-    void init() override;
-    Source *origin_;
-};
 
 
 #endif // SOURCE_H