CMIS-851: Fix NSInvalidArgumentException in [CMISObjectByIdUriBuilder buildUrl]

Added an assert for the objectId and path in the builder objects and added protection around relationship parameter (had the potential to be nil).

git-svn-id: https://svn.apache.org/repos/asf/chemistry/objectivecmis/trunk@1630752 13f79535-47bb-0310-9956-ffa450edef68
CMIS-852: Typo in CMISObjectService API

git-svn-id: https://svn.apache.org/repos/asf/chemistry/objectivecmis/trunk@1630753 13f79535-47bb-0310-9956-ffa450edef68