Phlogiston/Forecasting Model

This model does not attempt to predict changes in size of backlog.
 * 1) Calculate velocity per category
 * 2) Count number of resolved tasks each week, and compare week to week
 * 3) Today = base day, so last week = today - 7 days
 * 4) Make optimistic, nominal, and pessimistic forecasts of velocity
 * 5) Optimistic is the highest 3 weeks in the last 3 months
 * 6) Nominal is the average per week over the last 3 months
 * 7) Pessimistic is the worst 3
 * 8) For teams that resolve tasks every 2 weeks, and thus have a bunch of 0 weeks, this will produce a falsely low forecast
 * 9) If any forecast velocity is below 1 (point or count per week), increase to 1
 * 10) Divide the total points remaining (per category) by each of the three velocities to determine # of weeks remaining