Dynamic leaderboards feature. Merge #43

CHANGELOG.md

cmd/admin.go

glide.lock

glide.yaml

main.go

migrations/20170228205100_leaderboards.sql

server/api.proto

server/pipeline.go

server/pipeline_group.go

server/pipeline_leaderboard.go

server/pipeline_match.go

server/pipeline_self.go

server/pipeline_topic.go

server/presence_notifier.go

server/session.go

server/session_auth.go

server/session_registry.go

server/tracker.go