Bug 194371 Use page emitter framework to implement ppt emitter.
In order to keep consistent with pdf and postscript, ppt need to use page emitter framework.
engine/org.eclipse.birt.report.engine.emitter.ppt/src/org/eclipse/birt/report/engine/emitter/ppt/PPTEmitter.java
public void startData( IDataContent data )
	{
		return;
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.birt.report.engine.emitter.IContentEmitter#startForeign(org.eclipse.birt.report.engine.content.IForeignContent)
	 */
	public void startForeign( IForeignContent foreign )
	{
		return;
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.birt.report.engine.emitter.IContentEmitter#startImage(org.eclipse.birt.report.engine.content.IImageContent)
	 */
	public void startImage( IImageContent image )
	{
		return;
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.birt.report.engine.emitter.IContentEmitter#startLabel(org.eclipse.birt.report.engine.content.ILabelContent)
	 */
	public void startLabel( ILabelContent label )
	{
		return;