Bug 151361 default value for reousrce folder user preference
When user does not sepecify the resourec foler user preference, can we make the current project folder (in IDE) or the current report design file's folder (in RCP) as the default value for the resource folder. This way, by default the current project folder is the resource folder where user can create their libs and images. Also please set the default user preference to be null when BIRT is freshly installed.
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/ui/ReportPlugin.java
* This method is called when the plug-in is stopped
	 */
	public void stop( BundleContext context ) throws Exception
	{
		super.stop( context );
		cellLeftCursor.dispose( );
	}
	/**
	 * Returns the shared instance.
	 */
	public static ReportPlugin getDefault( )
	{
		return plugin;
	}
	/**
	 * Relative to UI plugin directory, example: "icons/usertableicon.gif".
	 * 
	 * @param key
	 * @return an Image descriptor, this is useful to preserve the original
	 *         color depth for instance.
	 */
	public static ImageDescriptor getImageDescriptor( String key )
	{
		ImageRegistry imageRegistry = ReportPlugin.getDefault( )
				.getImageRegistry( );
		ImageDescriptor imageDescriptor = imageRegistry.getDescriptor( key );
		if ( imageDescriptor == null )
		{
			URL url = ReportPlugin.getDefault( ).find( new Path( key ) );
			if ( null != url )