[gtkmm] Demo: Remove unnecessary typedefs.

[Murray Cumming <murrayc src gnome org>]

commit e8ce7956c51015803d82addc7597a1059e2233f4
Author: Murray Cumming <murrayc murrayc com>
Date:   Mon Nov 21 11:35:40 2016 +0100

    Demo: Remove unnecessary typedefs.
    
    These are not useful now that we use auto.

 demos/gtk-demo/example_treeview_editable_cells.cc |    3 +--
 demos/gtk-demo/example_treeview_liststore.cc      |    3 +--
 demos/gtk-demo/example_treeview_treestore.cc      |    3 +--
 3 files changed, 3 insertions(+), 6 deletions(-)
---
diff --git a/demos/gtk-demo/example_treeview_editable_cells.cc 
b/demos/gtk-demo/example_treeview_editable_cells.cc
index 6a2e761..aff59a2 100644
--- a/demos/gtk-demo/example_treeview_editable_cells.cc
+++ b/demos/gtk-demo/example_treeview_editable_cells.cc
@@ -52,8 +52,7 @@ protected:
   Gtk::Box m_HBox;
   Gtk::Button m_Button_Add, m_Button_Remove;
 
-  typedef std::vector<CellItem_Product> type_vecItems;
-  type_vecItems m_vecItems;
+  std::vector<CellItem_Product> m_vecItems;
 
   struct ModelColumns : public Gtk::TreeModelColumnRecord
   {
diff --git a/demos/gtk-demo/example_treeview_liststore.cc b/demos/gtk-demo/example_treeview_liststore.cc
index 1cf076b..f40c75d 100644
--- a/demos/gtk-demo/example_treeview_liststore.cc
+++ b/demos/gtk-demo/example_treeview_liststore.cc
@@ -41,8 +41,7 @@ protected:
   Gtk::TreeView m_TreeView;
   Glib::RefPtr<Gtk::ListStore> m_refListStore;
 
-  typedef std::vector<CellItem_Bug> type_vecItems;
-  type_vecItems m_vecItems;
+  std::vector<CellItem_Bug> m_vecItems;
 
   struct ModelColumns : public Gtk::TreeModelColumnRecord
   {
diff --git a/demos/gtk-demo/example_treeview_treestore.cc b/demos/gtk-demo/example_treeview_treestore.cc
index 87afd24..13646d0 100644
--- a/demos/gtk-demo/example_treeview_treestore.cc
+++ b/demos/gtk-demo/example_treeview_treestore.cc
@@ -52,8 +52,7 @@ protected:
   Gtk::TreeView m_TreeView;
   Glib::RefPtr<Gtk::TreeStore> m_refTreeStore;
 
-  typedef std::vector<CellItem_Holiday> type_vecItems;
-  type_vecItems m_vecItems;
+  std::vector<CellItem_Holiday> m_vecItems;
 
   struct ModelColumns : public Gtk::TreeModelColumnRecord
   {