Demo mode - log possible trades

[stixpunk]

I have blackbird running one week in demo mode and csv is empty (only header). Is there or can be added option to log possible trades to csv in demo mode? It will be helpful to see some results before run bot with real money.

[CCKRK]

Personally, I wouldn't want to nest action critical functions (like send order) in any loops for a feature like this. Without doing that, I think adding the feature to the current codebase would be a lot of work for very little payoff.

That being said, I don't want to discourage anyone from submitting a PR for a feature like this -- I'm sure it's in demand.