Payoff matrix using 4 colors

- The payoff matrix entries (CC,DC,CD,DD) are ordered and assign to a
  color (green,blue,yellow,red)
- For each entry in the detailed view, we assign the color to the
  closest kind of "mono-move" score e.g. T*payoff(move).

Would fix #1.
Merge pull request #7 from geeklhem/payoff_color

Payoff matrix using 4 colors