bump version to v0.9.0 now that py26 is not supported anymore

Author: wojcikstefan

setup.py

@@ -19,7 +19,7 @@
 
 setup(
     name='flask-mongoengine',
-    version='0.8.2',
+    version='0.9.0',
     url='https://github.com/mongoengine/flask-mongoengine',
     license='BSD',
     author='Ross Lawley',