User filter id can be changed. Handle service options e.g. omero.group
Optionally return cell array with annotations for each input ID
Rename uid optional parameter as owner for clarity

In the long run we may want to differentiate between the annotation owner
and the annotation link owner.
Propagate owner param/key value to the getObjectTypeAnnotations functions
Unify and improve description of owner/flatten parameters
Improve description of flatten option
Merge pull request #2284 from sbesson/matlab_annotation_owner

OMERO.matlab: add argument to retrieve annotation by owner