Add a bunch of factors from wikipedia
recency weighted
always return a list from get_previous_entry(), check for unset objects
check for unset objects
add some figures
fix surface
PctAvgBeyer is no more, use Pct(Avg(BeyerSpeedFigure)) instead. added get_previous_entry to BeyerSpeedFigure
some sanaty checks
added DistancePref and TrackPref, reworked PostPosition
better matching of surface
check for None instead of is not
add soem more figures
cutoff date added, and subtract weight from cutoff date
add Rank and get ride of all the *Rank
add multinomial regression