Feed the timeline sensible values when no trades have been done
Currently the timeline widget will get an emtpy vector if no trades have been done and the administrator has not explicitly set the prices.
This leads to an ugly chart, and it confuses d3 when the first trade is done.
In this situation the prices would be 100/(number of contracts) for each contract. This fact should be leveraged, and faux set-price events should be injected when no actual set-price events actually exists.