Search API response when no matches found

[greg-wiltshire]

The search API currently returns an empty object if there is no match found. I propose that this is modified to be

{searchResult: []}

which will mean that downstream code will not have to check for the property.

[martin-traverse]

I think this is a feature of protobuf and carried over to protobufjs, which is the foundation of our web API bindings. We might be able to address it with a generation option in the protobufjs code generation step, although that seems unlikely since this is the semantics of protobuf itself.