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
/**
	 * default constructor
	 */
	public LibraryExplorerView( )
	{
		super( );
	}
	/**
	 * Creates and returns the default page for this view.
	 * 
	 * @param book
	 *            the pagebook control
	 * @return the default page
	 */
	protected IPage createDefaultPage( PageBook book )
	{
		MessagePage page = new MessagePage( );
		initPage( page );
		page.createControl( book );
		page.setMessage( defaultText );
		return page;
	}
	/**
	 * Creates a new page in the pagebook for a particular part. This page will
	 * be made visible whenever the part is active, and will be destroyed with a
	 * call to <code>doDestroyPage</code>.
	 * 
	 * @param part
	 *            the input part
	 * @return the record describing a new page for this view