InMemory: simplify interfaces

git-svn-id: https://svn.apache.org/repos/asf/chemistry/opencmis/trunk@1515275 13f79535-47bb-0310-9956-ffa450edef68
InMemory: simplify interfaces

git-svn-id: https://svn.apache.org/repos/asf/chemistry/opencmis/trunk@1515276 13f79535-47bb-0310-9956-ffa450edef68