Asks the Steam back-end for a set of rows in the leaderboard.
This call is asynchronous, with the result returned in LeaderboardScoresDownloaded_t
LeaderboardScoresDownloaded_t will contain a handle to pull the results from GetDownloadedLeaderboardEntries() (below)
You can ask for more entries than exist, and it will return as many as do exist.
k_ELeaderboardDataRequestGlobal requests rows in the leaderboard from the full table, with nRangeStart & nRangeEnd in the range [1, TotalEntries]
k_ELeaderboardDataRequestGlobalAroundUser requests rows around the current user, nRangeStart being negate
e.g. DownloadLeaderboardEntries( hLeaderboard, k_ELeaderboardDataRequestGlobalAroundUser, -3, 3 ) will return 7 rows, 3 before the user, 3 after
k_ELeaderboardDataRequestFriends requests all the rows for friends of the current user