Try a better method to take top k things from list.

Unfortunately, it's not any faster... :(
Make it faster! 55s -> 34s with these changes
Merge branch 'master' into averaging

Conflicts:
	jams/learning/scala/src/main/scala/KnnCalculation.scala
Merge branch 'master' into averaging

Conflicts:
	jams/learning/scala/src/main/scala/KnnCalculation.scala
Initial commit