Bug 166015 Refactor designer actions to eclipse command framework
Eclipse command framework provide a more explicit way to manage UI actions contributions, we can take it's advantage to make our actions code more clean and maintainable.
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/internal/ui/views/actions/InsertAction.java
/**
	 * Create a new insert action with given selection and text at specified
	 * position
	 * 
	 * @param selectedObject
	 *            the selected object,which cannot be null
	 * @param text
	 *            the text of the action
	 * @param type
	 *            the type of the element to insert
	 * @param pos
	 *            the insert position
	 */
	public InsertAction( Object selectedObject, String text, String type,
			String pos )
	{
		this( selectedObject, text, null, type, pos );
	}
	public InsertAction( Object selectedObject, String text,
			SlotHandle slotHandle, String type, String pos )
	{
		super( selectedObject, text );
		this.type = type;
		this.position = pos;
		if ( slotHandle != null )
		{
			this.slotHandle = slotHandle;
		}
		else
		{