Two new classes: PortletUnitPortletRequest and PortletUnitPortletSession

Two new files have been added to the CVS tree, PortletUnitPortletSession and PortletUnitPortletRequest. These objects implement the PortletSession and PortletRequest objects. The only method implemented on the PortletRequest is getPortletSession and the PortletSession can only get and set APPLICATION_SCOPE attributes. The rest of the methods are all stubbed and will be implemented as needed.