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
* 
	 * @see org.eclipse.birt.report.engine.emitter.IContentEmitter#startTable(org.eclipse.birt.report.engine.content.ITableContent)
	 */
	public void startTable( ITableContent table )
	{
		return;
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.birt.report.engine.emitter.IContentEmitter#startText(org.eclipse.birt.report.engine.content.ITextContent)
	 */
	public void startText( ITextContent text )
	{
		return;
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.birt.report.engine.emitter.IContentEmitter#endGroup(org.eclipse.birt.report.engine.content.IGroupContent)
	 */
	public void endGroup( IGroupContent group )
	{
		return;
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.birt.report.engine.emitter.IContentEmitter#endListGroup(org.eclipse.birt.report.engine.content.IListGroupContent)
	 */