Implementation of #343 (dockable bookmark window)

Here is the proposal:
- There is a new panel similar to the layer list showing the
  bookmarks. It can be shown using View/Bookmarks.
  Initially this panel is hidden.
- Double-clicking on an item in this bookmark list will
  navigate to the bookmark.
- Context menu entries of this panel are: manage, load and
  save bookmarks (like in main menu)

In addition, "bookmark this view" now proposes a bookmark name
make of "B" and a unique number.

src/laybasic/laybasic/layBookmarksView.cc

@@ -23,6 +23,8 @@
 
 #include "layBookmarksView.h"
 #include "layLayoutView.h"
+#include "layAbstractMenu.h"
+#include "layAbstractMenuProvider.h"
 
 #include <QVBoxLayout>
 
@@ -100,7 +102,9 @@ BookmarksView::BookmarksView (LayoutView *view, QWidget *parent, const char *nam
   layout->addWidget (mp_bookmarks);
 
   mp_bookmarks->setModel (new BookmarkListModel (&view->bookmarks ()));
+  mp_bookmarks->setContextMenuPolicy (Qt::CustomContextMenu);
 
+  connect (mp_bookmarks, SIGNAL (customContextMenuRequested (const QPoint &)), this, SLOT (context_menu (const QPoint &)));
   connect (mp_bookmarks, SIGNAL (doubleClicked (const QModelIndex &)), this, SLOT (bookmark_triggered (const QModelIndex &)));
 }
 
@@ -109,6 +113,24 @@ BookmarksView::~BookmarksView ()
   //  .. nothing yet ..
 }
 
+void
+BookmarksView::init_menu (lay::AbstractMenu &menu)
+{
+  MenuLayoutEntry context_menu [] = {
+    MenuLayoutEntry ("manage_bookmarks",     tl::to_string (QObject::tr ("Manage Bookmarks")),    SLOT (cm_manage_bookmarks ())),
+    MenuLayoutEntry ("load_bookmarks",       tl::to_string (QObject::tr ("Load Bookmarks")),      SLOT (cm_load_bookmarks ())),
+    MenuLayoutEntry ("save_bookmarks",       tl::to_string (QObject::tr ("Save Bookmarks")),      SLOT (cm_save_bookmarks ())),
+    MenuLayoutEntry::last ()
+  };
+
+  MenuLayoutEntry main_menu [] = {
+    MenuLayoutEntry ("@bookmarks_context_menu", "", context_menu),
+    MenuLayoutEntry::last ()
+  };
+
+  menu.init (main_menu);
+}
+
 void
 BookmarksView::set_background_color (QColor c)
 {
@@ -134,6 +156,18 @@ BookmarksView::refresh ()
   }
 }
 
+void
+BookmarksView::context_menu (const QPoint &p)
+{
+  tl_assert (lay::AbstractMenuProvider::instance () != 0);
+
+  QListView *bm_list = dynamic_cast<QListView *> (sender ());
+  if (bm_list) {
+    QMenu *ctx_menu = lay::AbstractMenuProvider::instance ()->menu ()->detached_menu ("bookmarks_context_menu");
+    ctx_menu->exec (bm_list->mapToGlobal (p));
+  }
+}
+
 void
 BookmarksView::bookmark_triggered (const QModelIndex &index)
 {

src/laybasic/laybasic/layBookmarksView.h

@@ -35,6 +35,7 @@ namespace lay
 {
 
 class LayoutView;
+class AbstractMenu;
 
 /**
  *  @brief A widget to display a bookmark list
@@ -53,10 +54,13 @@ public:
 
   void refresh ();
 
+  static void init_menu (lay::AbstractMenu &menu);
+
 public slots:
   void bookmark_triggered (const QModelIndex &index);
+  void context_menu (const QPoint &p);
 
-public:
+private:
   LayoutView *mp_view;
   QListView *mp_bookmarks;
 };

src/laybasic/laybasic/layLayoutView.cc

@@ -840,6 +840,7 @@ LayoutView::init_menu (lay::AbstractMenu &menu)
   lay::LayerControlPanel::init_menu (menu);
   lay::HierarchyControlPanel::init_menu (menu);
   lay::LibrariesView::init_menu (menu);
+  lay::BookmarksView::init_menu (menu);
 }
 
 void