Fix shared pointer forward declaration

src/sourcetree/sourcetreeview.cpp

@@ -110,6 +110,8 @@ SourceTreeView::SourceTreeView( QWidget* parent )
 
 }
 
+SourceTreeView::~SourceTreeView()
+{}
 
 void
 SourceTreeView::setupMenus()

src/sourcetree/sourcetreeview.h

@@ -37,6 +37,7 @@ Q_OBJECT
 
 public:
     explicit SourceTreeView( QWidget* parent = 0 );
+    ~SourceTreeView();
 
 public slots:
     void showOfflineSources( bool offlineSourcesShown );