Bug 166236 [Viewers] ViewerColumn needs a dispose method
ViewerColumn adds a listener to its label provider which is never removed. We need a dispose method that removes the listener. Furthermore, if the column's label provider wraps a non-column-specific label provider, the viewer is already listening to it and the viewer column shouldn't. Must be fixed before the next I build.
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/ViewerColumn.java
private CellLabelProvider labelProvider;
	static String COLUMN_VIEWER_KEY = Policy.JFACE + ".columnViewer";
	private EditingSupport editingSupport;
	private ILabelProviderListener listener;
	/**
	 * Create a new instance of the receiver at columnIndex.
	 * 
	 * @param viewer
	 *            the viewer the column is part of
	 * @param columnOwner
	 *            the widget owning the viewer in case the widget has no columns
	 *            this could be the widget itself