Feature can be done

[dmigo]

Every feature can be done. Every turn we calculate the probability of a feature to be done. By formula:

P = (Progress - Feature size*0.5) / Feature Size

Intuition is: as soon as we are over half of the feature - there is a small probability to close it, as soon as we are over the feature size - the probability becomes more than 50%.

This isn't perfect, but will do for now.