Sharing render output between two canvases is broken

When creating two pipelines sharing the same dataContainer having the same _renderTargetID, the sharing of the render output is broken.

1. When interacting with one pipeline, the output of the other does not get updated (setPipelineDirty() is not called, missing onDataContainerAdded overload in AbstractPipeline)
2. Even if that is added, the other canvas often just shows a black screen.