Separate trade start logic from trade monitoring for exit

[sthewissen]

Currently the trade loop runs once for a given period. If for example you run the loop on 1 hour candles it runs the entire trade loop once every hour. This also means that active trades get checked for their exit conditions only once every hour. I think the trade monitoring for exit conditions could benefit from being a separate process that can run more often compared to the logic for finding a decent entry point.

[sthewissen]

A lot of this has been fixed by adding a SellTimer next to the BuyTimer on develop.