Contract dry-runs should return the events that would be emitted.

This will e.g. enable user interfaces to indicate better what the consequence of signing and submitting a particular transaction is.

A current UX movement for blockchains is to counter the "blind sign and submit" behavior ("yolo sign and submit"). We should provide better means to assess the effect of a transaction before submitting; returning the events that would be emitted would be a major step towards that.