corrected the content type of VaadinLiferayPortletDescriptorHelper
IDE-1537 ensure that java facet is 1.6 or greater
IDE-1546 added operation of updating descriptor file

maven project uses the lastest version of archetype, which may conflict
with user selected profile, remove <requires-namespaced-parameters>
element in liferay-portlet.xml of 6.1.x version jsf-portlet project.
IDE-1539 Added the unit tests for server core and ServerManagerTests