make event order check a configuration setting

services/real-time/app/coffee/DocumentUpdaterController.coffee

@@ -34,7 +34,7 @@ module.exports = DocumentUpdaterController =
 				logger.error {err: error, channel}, "error parsing JSON"
 				return
 			if message.op?
-				if message._id?
+				if message._id? && settings.checkEventOrder
 					status = EventLogger.checkEventOrder("applied-ops", message._id, message)
 					if status is 'duplicate'
 						return # skip duplicate events

services/real-time/app/coffee/WebsocketLoadBalancer.coffee

@@ -41,7 +41,7 @@ module.exports = WebsocketLoadBalancer =
 			if message.room_id == "all"
 				io.sockets.emit(message.message, message.payload...)
 			else if message.room_id?
-				if message._id?
+				if message._id? && Settings.checkEventOrder
 					status = EventLogger.checkEventOrder("editor-events", message._id, message)
 					if status is "duplicate"
 						return # skip duplicate events

services/real-time/config/settings.defaults.coffee

@@ -52,6 +52,8 @@ settings =
 
 	continualPubsubTraffic: process.env['CONTINUAL_PUBSUB_TRAFFIC'] or false
 
+	checkEventOrder: process.env['CHECK_EVENT_ORDER'] or false
+	
 	sentry:
 		dsn: process.env.SENTRY_DSN