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.lib.explorer/src/org/eclipse/birt/report/designer/ui/lib/explorer/LibraryExplorerView.java
* @see #doCreatePage
	 */
	protected void doDestroyPage( IWorkbenchPart part, PageRec pageRecord )
	{
		IPage page = pageRecord.page;
		page.dispose( );
		pageRecord.dispose( );
	}
	/**
	 * Returns the active, important workbench part for this view.
	 * <p>
	 * When the page book view is created it has no idea which part within the
	 * workbook should be used to generate the first page. Therefore, it
	 * delegates the choice to subclasses of <code>PageBookView</code>.
	 * </p>
	 * <p>
	 * Implementors of this method should return an active, important part in
	 * the workbench or <code>null</code> if none found.
	 * </p>
	 * 
	 * @return the active important part, or <code>null</code> if none
	 */
	protected IWorkbenchPart getBootstrapPart( )
	{
		IWorkbenchPage page = getSite( ).getPage( );
		if ( page != null )
		{
			return page.getActiveEditor( );
		}
		return null;