Update documentation

docs/reference/utils.rst

@@ -11,15 +11,24 @@ This module provides helper functions.
 
 .. function:: disable_ap()
 
+    Function to disable the device Wifi Access Point. For the ESP8266 Microhomie firmwares this function will be excecuted on boot.
 
 .. function:: get_unique_id()
 
+    Return a unique device id as bytestring.
 
 .. function:: get_local_ip()
 
+    Return the device IP address, if possible.
 
 .. function:: get_local_mac()
 
+    Return the device MAC address, if possible.
 
 .. function:: payload_is_valid()
 
+    Helper function to validate payload for node properties.
+
+    This function does only test if the payload match the datatype, but the format the payload has to be in, for now.
+
+    Returns ``True`` or ``False``.