- Add lookup method for looking up objects with specified set of types
in CommunityCtxDB.
- Implement lookup method.
- Add lookup up method in UserCtxDB for looking up for sets of
ctxidentifier given a set of types. 
- Implement lookup method. 
- Implement local tests for LookupSetOfTypes.
internal and external ctxbroker interface updated with lookup methods
that
exploit
data
hierarchies. Integration test ctx-lookableDataTypes tests new
functionality.
lookable datatypes functionality updates
Merge branch 'ContextManagement_lookup' into development