CMIS-774: added hasAllowableAction and getPermissonsForPrincipal

git-svn-id: https://svn.apache.org/repos/asf/chemistry/opencmis/trunk@1597992 13f79535-47bb-0310-9956-ffa450edef68
CMIS-807: Workbench: handle incompliant repositories that don't provide allowable actions (and using the new convenience methods)

git-svn-id: https://svn.apache.org/repos/asf/chemistry/opencmis/trunk@1597994 13f79535-47bb-0310-9956-ffa450edef68