Assign Medals correctly for single elim.
Assign Medals correctly for single elim.

 - Actually use the finals matches for assigning medals when there is a
   finals. fixes #80 and fixes #74
 - DRY up assignMedals() a bit.
 - Rename assignTropiesFromMatches (sic) to assignMedalsBySingleElim for
   consistency, and move it for locality of reference.

jamuraa/gatherling