Some root classes are still emitted

[gordonwatts]

It seems like we are still trying to emit a few ROOT classes. From some recent work, I'm seeing:

ERROR: Cannot emit method TVector3::Execute - some types not emitted.
ERROR: Cannot emit method TVector3::ExecuteEvent - some types not emitted.
ERROR: Cannot emit method TVector3::FindObject - some types not emitted.
ERROR: Cannot emit method TVector3::GetDrawOption - some types not emitted.