Handle config options reserved by Flask.
On second thought, do not treat Flask reserved options differently.

It is unlikely that I will wish to have conflicts with the Flask
reserved options and it doesn't make any sense for the user to have
some options be case-sensitive and others not.
Allow config to read from a file-like object.
Initialize application with config file data.

Additionally, add a wsgi module that Twisted/Gunicorn can import an app
from.