Update version to 0.7.2

1. Update index.rst
1. Updated index.rst
1. Make the config easier to override.
1. Fix bug to allow multiple instances of extension.
1. Fix dangerous use self.app in init_app and test refactoring.
1. MongoEngineSessionInterface can now timezone aware dates
1. Support arbitrary primary key fields
1. Update app.py
1. Fix typo
1. Configurable httponly flag for MongoEngineSessionInterface
1. Improve settings parsing: allows and emphasizes MongoDB URI usage in configuration

setup.py

@@ -22,7 +22,7 @@
 
 setup(
     name='flask-mongoengine',
-    version='0.7.1',
+    version='0.7.2',
     url='https://github.com/mongoengine/flask-mongoengine',
     license='BSD',
     author='Ross Lawley',