onClick events don't return layerId

[hdmm3]

Describe the bug It is not possible to identify which layer is triggering an onClick event, since the JSON event returned by md_layer_click is assigning a non-existent value to layerId.

Expected behaviour The picking info object returns a layer object instead of returning directly a layer_id . The layerId should be obtained from info.layer.id instead of info.layer_id

[dcooley]

thanks - have just updated master branch.