Revision 1452

* Thuban/Model/layer.py (Layer.__init__): Rename
classificationField to classificatin_column and init it here so
that it can be used in SetClassificationColumn
(Layer.GetClassificationColumn, Layer.GetClassificationField):
Rename to GetClassificationColumn.
(Layer.SetClassificationColumn, Layer.SetClassificationField):
Rename to SetClassificationColumn and issue a LAYER_CHANGED
message if the column changes.
(Layer._classification_changed, Layer.ClassChanged): Rename to
_classification_changed. Update the callers.
(Layer.SetShapeStore): Further field->column renames.

* Thuban/Model/load.py (SessionLoader.start_classification)
(SessionLoader.start_clpoint): Updates because of
field->column method name changes in the Layer class

* Thuban/Model/save.py (SessionSaver.write_classification): Updates
because of field->column method name changes in the Layer class

* Thuban/UI/classifier.py (Classifier.__init__)
(Classifier._OnTry, Classifier._OnRevert): Updates because of
field->column method name changes in the Layer class

* Thuban/UI/renderer.py (MapRenderer.draw_shape_layer): Updates
because of field->column method name changes in the Layer class

* Thuban/UI/viewport.py (ViewPort.find_shape_at): Updates because
of field->column method name changes in the Layer class

* test/test_save.py (SaveSessionTest.testClassifiedLayer)
(SaveSessionTest.testClassifiedLayer): Update because of
field->column method name changes in the Layer class

* test/test_layer.py (SetShapeStoreTests.setUp)
(SetShapeStoreTests.test_sanity): Update because of field->column
method name changes in the Layer class
(TestLayerModification.setUp): Subscribe to LAYER_CHANGED as well
(TestLayerModification.test_sanity)
(TestLayerModification.test_initial_settings): remove unsued code
and rename to test_sanity.
(TestLayerModification.test_set_classification): New test for
SetClassification and SetClassificationField.