add connect() to the very first example (#1270)

Author: alexandrecuer

README.rst

@@ -104,6 +104,7 @@ For those of you that just want to get started fast, here you go::
     from pymodbus.client import ModbusTcpClient
 
     client = ModbusTcpClient('127.0.0.1')
+    client.connect()
     client.write_coil(1, True)
     result = client.read_coils(1,1)
     print(result.bits[0])