Add Campaigns for Apps to the Readme

The Readme did not reference the Campaigns for Apps functionality yet.
Also the headers within the Readme were not rendered properly.

Author: Teun Zengerink

README.MD

@@ -1,4 +1,4 @@
-#Usabilla API - Python Client
+# Usabilla API - Python Client
 
 [![Build Status](https://travis-ci.org/usabilla/api-python.svg?branch=master)](https://travis-ci.org/usabilla/api-python)
 [![PyPI version](https://badge.fury.io/py/usabilla-api.svg)](https://badge.fury.io/py/usabilla-api)
@@ -7,7 +7,8 @@
 The Usabilla Python client allows users to access data from their Usabilla accounts.
 It makes use of the API to request the following products and resources:
 
-###Usabilla for Websites
+### Usabilla for Websites
+
 - Buttons
 - Feedback items
 - Campaigns
@@ -16,13 +17,17 @@ It makes use of the API to request the following products and resources:
 - In-Page widgets
 - In-Page feedback
 
-###Usabilla for Email
-  - Buttons
-  - Feedback items
+### Usabilla for Email
+
+- Buttons
+- Feedback items
+
+### Usabilla for Apps
 
-###Usabilla for Apps
-  - Apps
-  - Feedback items
+- Apps
+- Feedback items
+- Campaigns
+- Campaign results
 
 For more information on resources, authorization and available API calls, please visit out [documentation](https://usabilla.com/api).
 
@@ -35,15 +40,15 @@ pip install usabilla-api
 ```
 
 ## Examples
-The example folder contains an  example of the client, which gives an idea how the client can be used and what is possible.
 
+The example folder contains an  example of the client, which gives an idea how the client can be used and what is possible.
 
-###Iterators
+### Iterators
 
 When working with the <code>limit</code> parameters (default value is **100**) you can request resources using the <code>item_iterator()</code> function.
 The API returns data in pages. This function returns a [Generator](https://wiki.python.org/moin/Generators) which
 traverses these pages for you and yields each result in the current page before retrieving the next page.
 
-##Support
+## Support
 
 The Usabilla Python Client API is maintained by Usabilla Development Team. Everyone is encouraged to file bug reports, feature requests, and pull requests through GitHub. This input is critical and will be carefully considered, but we can’t promise a specific resolution or time frame for any request. For more information please email our Support Team at [email protected]