Update readme for new behavior

Author: nordic-olha

README.md

@@ -1,7 +1,7 @@
 nrf51-ble-app-lbs
 ==================
 
-This is the accompanying code for the application note nAN-36: "Creating Bluetooth Low Energy Applications Using nRF51822". It is an implemtation of a simple application that shows a custom service with two characteristics; one for a button and one for a LED. The button characteristic will send a notification on each toggle of a button, while the LED characteristic can be used to control an on-board LED.
+This is the accompanying code for the application note nAN-36: "Creating Bluetooth Low Energy Applications Using nRF51822". It is an implemtation of a simple application that shows a custom service with two characteristics; one for a button and one for a LED. The button characteristic will send a notification with the button state when the button is pressed or released, while the LED characteristic can be used to control an on-board LED.
 
 Requirements
 ------------