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
* Inserts the library to the given position.
	 * 
	 * @param library
	 *            the library to insert
	 * @param posn
	 *            at which the given library is inserted.
	 */
	public void insertLibrary( Library library, int posn )
	{
		if ( libraries == null )
			libraries = new ArrayList( );
		
		assert posn >= 0 && posn <= libraries.size( );
		libraries.add( posn, library );
	}
	/**
	 * Adds the given libray to library list.
	 * 
	 * @param library
	 *            the library to insert
	 */
	public void addLibrary( Library library )
	{
		if ( libraries == null )
			libraries = new ArrayList( );
		libraries.add( library );
	}
	/**
	 * Drops the given library from library list.
	 *