StyleInputToGameInput changed to take a vector to return values in to handle multiple inputs mapped to a single column. Associated adjustments to everything that uses it.
Player no longer drops holds in columns that have multiple inputs mapped to them if the wrong one is held.
Running out of stage tokens changed from assert to error.
7534867: fix SSM crashes when selecting a song with only one player enabled
cddaab5: simplify SongUtil::GetStepsTypeAndDifficultyFromSortOrder
615aab0: add Style::GetUsesCenteredArrows (doubles + routine)
17f38e7: sanity check
[all code changes by Glenn Maynard]