Bbr Helper

This provides some advanced stats (game score, simple player rating and game box plus-minus) on multiple pages for NBA, WNBA, G-League, international leagues and college basketball.

Including:
- average stats by season on the player page
- average stats by playoff series on the player page
- average stats by player on the team_season page
- average stats by player on the team_player page
- average stats by player on the season_player page
- single game/half/quarter stats by player on the game_boxscore page
- single game and average stats on the gamelog and split pages
- top 5 and top 20 average stats players on the season page
- top 20 average stats players on the team_season page
- top 20 average stats seasons rankings on the player page
- top 50 career stats rankings on the player page
- multiple stats rankings on the leader page
- player awards column on team season page

They are calculated as:
"""
GmSc = (pts + 0.4 * fg - 0.7 * fga + 0.4 * ft - 0.4 * fta + 0.7 * orb + 0.3 * drb + 0.42 * (trb - orb - drb) + stl + 0.7 * ast + 0.7 * blk - 0.4 * pf - tov) / g

SPR = (pts - fga + 0.2 * fg3a - 0.3 * fta + 0.3 * orb + 0.2 * drb + 0.23 * (trb - orb - drb) + 1.5 * stl + 0.5 * ast + 0.7 * blk - 1.2 * tov) / g

gBPM = (-0.55 * fga + 1.04 * fg3 + 1.39 * fg - 0.25 * fta + 0.79 *ft + 0.17 * orb + 0.27 * drb + 0.24 * (trb - orb - drb) + 1.34 * stl + 0.43 * ast + 0.64 * blk - 0.34 * pf - 0.95 * tov) / g
"""
, where orb is treated as 0.3 * trb and drb is treated as 0.7 * trb approximately when stats are not complete in early years.