Moves largerapp into patterns dir and add test

- also adds this pattern into tox for testing

tox.ini

@@ -10,6 +10,7 @@ commands =
     # We need to install those after Flask is installed.
     pip install -e examples/flaskr
     pip install -e examples/minitwit
+    pip install -e examples/patterns/largerapp
     py.test --cov=flask --cov-report html []
 deps=
     pytest