Remove useless using std

src/collection/collectiondirectorymodel.cpp

@@ -34,8 +34,6 @@
 #include "collectionbackend.h"
 #include "collectiondirectorymodel.h"
 
-using std::shared_ptr;
-
 CollectionDirectoryModel::CollectionDirectoryModel(CollectionBackend *backend, QObject *parent)
     : QStandardItemModel(parent),
       dir_icon_(IconLoader::Load("document-open-folder")),

src/collection/collectionview.cpp

@@ -64,8 +64,6 @@
 #include "organise/organisedialog.h"
 #include "settings/collectionsettingspage.h"
 
-using std::unique_ptr;
-
 CollectionView::CollectionView(QWidget *parent)
     : AutoExpandingTreeView(parent),
       app_(nullptr),

src/collection/collectionview.h

@@ -47,8 +47,6 @@ class CollectionFilterWidget;
 class EditTagDialog;
 class OrganiseDialog;
 
-using std::unique_ptr;
-
 class CollectionView : public AutoExpandingTreeView {
   Q_OBJECT