Bug 179931 Provide new interface IStyle to let extension return the style properties values
Provide the IStyle interface to let extension user can return the style property value list for their extension elements.
model/org.eclipse.birt.report.model.tests/test/org/eclipse/birt/report/model/extension/PeerExtensionTest.java
{
	protected static final String HEADER_PROP = "header"; 
	protected static final String DETAIL_PROP = "detail"; 
	protected static final String FOOTER_PROP = "footer"; 
	protected static final String TESTING_BOX_NAME = "TestingBox"; 
	private static final String FILE_NAME = "PeerExtensionTest.xml"; 
	private static final String FILE_NAME_1 = "PeerExtensionTest_1.xml"; 
	private static final String FILE_NAME_2 = "PeerExtensionTest_2.xml"; 
	private static final String FILE_NAME_3 = "PeerExtensionTest_3.xml"; 
	private static final String FILE_NAME_5 = "PeerExtensionTest_5.xml";
	private static final String FILE_NAME_6 = "PeerExtensionTest_6.xml"; 
	private static final String FILE_NAME_7 = "PeerExtensionTest_7.xml"; 
	private static final String POINTS_PROP_NAME = "points"; 
	private static final String TESTING_TABLE_NAME = "TestingTable"; 
	/**
	 * The extension do not have its own model.
	 */
	private static final String FILE_NAME_4 = "PeerExtensionTest_4.xml";