Correct readme

README.md

@@ -119,12 +119,13 @@ Prepare and start a BKCentral object with a configuration holding the UUIDs you
 ```swift
 let central = BKCentral()
 central.delegate = self
+central.addAvailabilityObserver(self)
 do {
 	let serviceUUID = NSUUID(UUIDString: "6E6B5C64-FAF7-40AE-9C21-D4933AF45B23")!
 	let characteristicUUID = NSUUID(UUIDString: "477A2967-1FAB-4DC5-920A-DEE5DE685A3D")!
 	let configuration = BKConfiguration(dataServiceUUID: serviceUUID, dataServiceCharacteristicUUID: characteristicUUID)
 	try central.startWithConfiguration(configuration: configuration)
-	// You are now ready to discover and connect to peripherals.
+	// Once the availability observer has been positively notified, you're ready to discover and connect to peripherals.
 } catch let error {
 	// Handle error.
 }