Merge remote-tracking branch 'origin/master' into metrics

lib/gat/admin/admin.go

lib/gat/database/database.go

lib/gat/database/query_router/query_router_test.go

lib/gat/gatling/client/client.go

lib/gat/gatling/gatling.go

lib/gat/gatling/server/server.go

lib/gat/interfaces.go

lib/gat/pool/session/pool.go

lib/gat/pool/transaction/worker.go