Add ds18b20 udp broadcaster example.

Add license and readme details.
Rid of compile-time switches.
Rid of lazy initialization of sensor.
Minor code fixing.

examples/ds18b20_broadcaster/README.md

@@ -0,0 +1,20 @@
+# DS19B20 Broadcaster
+
+>In this example you can see how to get data from multiple 
+>ds18b20 sensor and emit result over udb broadcaster address.
+
+As a client server, you can use this simple udp receiver, writen in python:
+
+```
+import select, socket
+
+s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+s.bind(('<broadcast>', 8005))
+s.setblocking(0)
+
+while True:
+    result = select.select([s],[],[])
+    msg = result[0][0].recv(1024)
+    print msg.strip()
+
+```