Tagset 133281 + bugfix for non trivial multithread issue. 

@Dr15Jones modified in #17 the API of RunPrincipal and LumiPrincipal to take a StreamID... This broke the compilation of #38 which was developed in parallel and does not have the new API.

This pull request fixes the issue by passing an StreamID::invalidSteamID. @wmtan, @Dr15Jones, can you please confirm this is the correct thing to do?