Bug 120315 If the display property of an item is set to "none", it doesn't take effect in new pdf emitter.
Description: If the display property of an item is set to "null", it doesn't take effect in new pdf emitter. steps to reproduce: 1. Add a label. 2. Open "properties" view. 3. Set section>Display as "none". 4. Preview in PDF. Expected result: the label disappears. Actual result: the label is still visible.
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/css/engine/value/birt/VisibleFormatManager.java
* The identifier values.
	 */
	protected final static StringMap values = new StringMap();
	static {
		values
				.put(BIRTConstants.BIRT_ALL_VALUE,
						BIRTValueConstants.ALL_VALUE);
	}
	/**
	 * Implements {@link ValueManager#isInheritedProperty()}.
	 */
	public boolean isInheritedProperty() {
		return true;
	}
	/**
	 * Implements {@link ValueManager#getPropertyName()}.
	 */
	public String getPropertyName() {
		return BIRTConstants.BIRT_VISIBLE_FORMAT_PROPERTY;
	}
	/**
	 * Implements {@link ValueManager#getDefaultValue()}.
	 */
	public org.eclipse.birt.report.engine.css.engine.value.Value getDefaultValue() {
		return DEFAULT_VALUE;
	}
	/**
	 * Implements {@link ValueManager#createValue(LexicalUnit,CSSEngine)}.
	 */
	public Value createValue(LexicalUnit lu, CSSEngine engine)