Fix for "10th score" leaderboard bug, Reduce load from GAMESTATE::StoreRankingName()

- Fixes bug where 10th scores get erased when two players play the same song multiple times and rank on the leaderboard more than once
- Only clamping leaderboards and deduping high scores for songs/courses once overall instead of once per player
- Instead of looping through every song and course on the machine multiple times -> Only loop through the songs/course played in the past session

src/GameState.h

@@ -357,6 +357,7 @@ public:
 	bool AnyPlayerHasRankingFeats() const;
 	void StoreRankingName( PlayerNumber pn, RString name );	// Called by name entry screens
 	std::vector<RString*> m_vpsNamesThatWereFilled;	// filled on StoreRankingName,
+	std::set<PlayerNumber> m_sPlayersThatWereFilled;	// filled on StoreRankingName,
 
 	// Award stuff
 	// lowest priority in front, highest priority at the back.