Calcluate consensus score. This is a heuristic for the percentage of the community who finds a term useful. Based on the observation that not every user will vote on a given term, user reptuation is used to estimate consensus. As the number of voters approaches the number of users, the votes become more equitable. (See doc/Scoring.pdf for details.)
Parameters: 


Calculate term stability, returning the time point when the term become stable (as a datetime.datetime) or None if it’s not stable. This is based on the rate of change of the consensus score:
delta_S = (S  P_s) / (T_now  T_last)
Parameters: 


The maximum varation in consensus allowed for score to be considered stable (S/hour).
Convert seconds (datetime.timedelta.seconds) to hours.
Interval (in hours) for which a term must be stable in order to be classified.
Classify stable term as canonical.
Classify stable term as deprecated.