Revision 535

Implement multiple selected shapes

* Thuban/UI/selection.py: New module with a class to represent the
selection.

* Thuban/UI/messages.py (SELECTED_TABLE, SELECTED_MAP): Remove
these unused messages

* Thuban/UI/application.py (ThubanApplication.OnInit)
(ThubanApplication.OnExit, ThubanApplication.SetSession): The
interactor is gone now.
(ThubanApplication.CreateMainWindow): There is no interactor
anymore so we pass None as the interactor argument for now for
compatibility.

* Thuban/UI/view.py (MapCanvas.delegated_messages)
(MapCanvas.Subscribe, MapCanvas.Unsubscribe): In Subscribe and
Unsubscribe, delegate messages according to the delegated_messages
class variable.
(MapCanvas.__getattr__, MapCanvas.delegated_methods): Get some
attributes from instance variables as described with the
delegated_methods class variable.
(MapCanvas.__init__): New instance variable selection holding the
current selection
(MapCanvas.do_redraw): Deal with multiple selected shapes. Simply
pass them on to the renderer
(MapCanvas.SetMap): Clear the selection when a different map is
selected.
(MapCanvas.shape_selected): Simple force a complete redraw. The
selection class now takes care of only issueing SHAPES_SELECTED
messages when the set of selected shapes actually does change.
(MapCanvas.SelectShapeAt): The selection is now managed in
self.selection

* Thuban/UI/mainwindow.py (MainWindow.delegated_messages)
(MainWindow.Subscribe, MainWindow.Unsubscribe): In Subscribe and
Unsubscribe, delegate messages according to the delegated_messages
class variable.
(MainWindow.delegated_methods, MainWindow.__getattr__): Get some
attributes from instance variables as described with the
delegated_methods class variable.
(MainWindow.__init__): The interactor as ivar is gone. The
parameter is still there for compatibility. The selection messages
now come from the canvas.
(MainWindow.current_layer, MainWindow.has_selected_layer):
Delegate to the the canvas.
(MainWindow.LayerShowTable, MainWindow.Classify)
(MainWindow.identify_view_on_demand): The dialogs don't need the
interactor parameter anymore.

* Thuban/UI/tableview.py (TableFrame.__init__)
(LayerTableFrame.__init__, LayerTableFrame.OnClose)
(LayerTableFrame.row_selected): The interactor is gone. It's job
from the dialog's point of view is now done by the mainwindow,
i.e. the parent. Subscribe to SHAPES_SELECTED instead
of SELECTED_SHAPE

* Thuban/UI/dialogs.py (NonModalDialog.__init__): The interactor
is gone. It's job from the dialog's point of view is now done by
the mainwindow, i.e. the parent.

* Thuban/UI/classifier.py (Classifier.__init__): The interactor is
gone. It's job from the dialog's point of view is now done by the
mainwindow, i.e. the parent.

* Thuban/UI/tree.py (SessionTreeView.__init__): The interactor is
gone. It's job from the dialog's point of view is now done by the
mainwindow, i.e. the parent.
(SessionTreeCtrl.__init__): New parameter mainwindow which is
stored as self.mainwindow. The mainwindow is need so that the tree
can still subscribe to the selection messages.
(SessionTreeCtrl.__init__, SessionTreeCtrl.unsubscribe_all)
(SessionTreeCtrl.update_tree, SessionTreeCtrl.OnSelChanged): The
selection is now accessible through the mainwindow. Subscribe to
SHAPES_SELECTED instead of SELECTED_SHAPE

* Thuban/UI/identifyview.py (IdentifyView.__init__): Use the
SHAPES_SELECTED message now.
(IdentifyView.selected_shape): Now subscribed to SHAPES_SELECTED,
so deal with multiple shapes
(IdentifyView.__init__, IdentifyView.OnClose): The interactor is
gone. It's job from the dialog's point of view is now done by the
mainwindow, i.e. the parent.

* Thuban/UI/renderer.py (ScreenRenderer.RenderMap): Rename the
selected_shape parameter and ivar to selected_shapes. It's now a
list of shape ids.
(MapRenderer.draw_label_layer): Deal with multiple selected
shapes. Rearrange the code a bit so that the setup and shape type
distinctions are only executed once.