Add Top N Equal Split method

It distributes the awards equally between the top N% of players.
The method receives one extra parameter: "ratio".
If "ratio" equals 0.25 then the awards are distributed among 25% of the best players.
If "ratio" equals 0.50 among 25% and so on.

If case of a tie the prizes are split and given equally to the tied players.
Merge pull request #2 from Picklive/top_n_equal_split

Add Top N Equal Split method