SolarElo

Added the rank-difference-scaling system to config.yml, which automatically adjusts the amount of Elo gained/lost based on the Rank gap between two players. Lower Rank defeats Higher Rank: Automatically grants an additional % Elo bonus based on the number of Rank tiers between the two players (Default: +15% Elo per Rank tier difference).

Higher Rank defeats Lower Rank: Automatically reduces the Elo gained (Default: -15% Elo per Rank tier difference) to prevent high-ranked players from farming newbies.

Added the mathematical variables {killer_rank_tier}, {victim_rank_tier}, and {rank_diff} to FormulaEvaluator for use with the CUSTOM formula mode.