Bunch of changes and enhancements

- Added caching for depth charts based on season/date.
- Added n limit for number of games to evaluate for calculate_pace and
calculate_defense_vs_position.
- Added date option for get_avg_stat_past_n_games.
- Added minutes evaluation to regression csv.
- Random changes from messing around with projections.
Reverted projection calculation back to what's in the master branch.
Merge branch '20140123_minutes_based_projections'
Modified some print statements

Modified the alert of a player being traded to include the player id
and removed the print that alerts us we’ve already accounted for an
injury - this was 99% of the output and making it impossible to see
when something did get detected.