Updated README with info and example.

Author: jburhenn

README.rst

@@ -1,9 +1,78 @@
 Cayenne MQTT Python Library
-===========================
-The Cayenne MQTT Python Library provides functions to easily connect to the Cayenne IoT project builder. It supports Python 2.7 or 3.x.
+***************************
+The Cayenne MQTT Python Library provides functions to easily connect to the `Cayenne IoT project builder <https://www.cayenne-mydevices.com>`_. With it you can send data to and receive data from Cayenne.
 
-This library installs the `Eclipse Paho MQTT Python client <https://github.com/eclipse/paho.mqtt.python>`_.
+Requirements
+============
+* `Python 2.7 or 3.x <https://www.python.org/downloads/>`_.
+* `This library <https://github.com/myDevicesIoT/Cayenne-MQTT-Python/archive/master.zip>`_.
+* `Eclipse Paho MQTT Python client library <https://github.com/eclipse/paho.mqtt.python>`_. This is installed as part of the Cayenne library installation.
 
+Getting Started
+===============
+Installation
+------------
+This library can be installed using pip:
+::
+
+  pip install cayenne-mqtt
+
+It can also be installed from the repository:
+::
+
+  git clone https://github.com/myDevicesIoT/Cayenne-MQTT-Python
+  cd Cayenne-MQTT-Python
+  python setup.py install
+  
+Cayenne Setup
+-------------
+1. Create your Cayenne account at https://www.cayenne-mydevices.com.
+2. Add a new device using the Bring Your Own Thing API selection.
+
+Examples
+--------
+Simple examples are available in the repository here: https://github.com/myDevicesIoT/Cayenne-MQTT-Python/tree/master/examples.
+
+Below is an example of a simple client that publishes some sample data and receives data from Cayenne in a message callback. The Cayenne authentication variables must be modified with the authentication info you received when adding a new device in Cayenne:
+::
+
+  import cayenne.client
+  import time
+
+  # Cayenne authentication info. This should be obtained from the Cayenne Dashboard.
+  MQTT_USERNAME  = "MQTT_USERNAME"
+  MQTT_PASSWORD  = "MQTT_PASSWORD"
+  MQTT_CLIENT_ID = "MQTT_CLIENT_ID"
+
+  # The callback for when a message is received from Cayenne.
+  def on_message(message):
+    print("message received: " + str(message))
+    # If there is an error processing the message return an error string, otherwise return nothing.
+    
+  client = cayenne.client.CayenneMQTTClient()
+  client.on_message = on_message
+  client.begin(MQTT_USERNAME, MQTT_PASSWORD, MQTT_CLIENT_ID)
+
+  i=0
+  timestamp = 0
+
+  while True:
+    client.loop()
+    
+    if (time.time() > timestamp + 10):
+      client.celsiusWrite(1, i)
+      client.luxWrite(2, i*10)
+      client.hectoPascalWrite(3, i+800)
+      timestamp = time.time()
+      i = i+1
+
+Documentation
+-------------
+For more detailed info about the Cayenne client API you can use **pydoc**.
+::
+
+  pydoc cayenne.client
+  
 
 Additional Cayenne MQTT Libraries
 =================================