Bug 152828 Add the projectFolder property on module
When user doesn't set the resource folder path in designer, there should be a default working path for Birt to manage the report design and find the related resources. A new property should be added on Module: name: projectFolder type:URL This property only can be given from the open design method from session but should not be set after the module initialized. Concern about the backward compatiblity issue, a new method will be added. Open design with a config argument.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/core/Module.java
* basing "base" property of module;
	 * <li>Search file with the file locator (<code>IResourceLocator</code>)
	 * in session.
	 * </ul>
	 * 
	 * @param fileName
	 *            file name to search
	 * @param fileType
	 *            file type. The value should be one of:
	 *            <ul>
	 *            <li><code>IResourceLocator.IMAGE</code>
	 *            <li><code>IResourceLocator.LIBRARY</code>
	 *            </ul>
	 *            Any invalid value will be treated as
	 *            <code>IResourceLocator.IMAGE</code>.
	 * @return the <code>URL</code> object if the file with
	 *         <code>fileName</code> is found, or null otherwise.
	 */
	public URL findResource( String fileName, int fileType )
	{
		URL url = getSession( ).getResourceLocator( ).findResource(
				(ModuleHandle) getHandle( this ), fileName, fileType );
		return url;
	}
	/**
	 * Loads library with the given library file name. This file name can be
	 * absolute or relative. If the library doesn't exist or fatal error occurs
	 * when opening library, one invalid library will be added into the library
	 * list of this module.
	 *