Fixed copyright dates
Replaced glade_design_layout_find_inside_container() with new private API
_glade_design_layout_get_child_at_position()
Added GtkOverlay support
Fixed rendering issues now that we support GtkOverlay and overlay children can be outside of its parent allocation.
Drag&Drop clean up.

Added private _GladeDrag interface. (only used internaly in gladeui)

Implemented _GladeDrag in GladePlaceholder GladeWidget GladeDesignView and GladeDesignLayout

Added drag-dest property to GladeWidget to enable/disable drag support
(used in GtkFixed GtkLayout and GtkOverlay containers)

Made GladeInspector a drag source by implementing GtkTreeDragSource interface in GladeProject
Added GtkApplicationWindow to the catalog
Added GtkOverlay icons
Moved GtkSelectionMode displayable values from GtkTreeview to GtkListBox
because it needs it earlier
Added missing AtkRole displayable values
Added icons for GtkListBox and GtkListBoxRow
Added GtkSearchEntry icons