Fix style on #lefty in narrow screen mode.

Now it looks like the main content box.
Set threadsafe: true.

- use WSGI handlers
- stop setting redundant mapreduce handlers in app.yaml

Also, delete old appengine_config.py. We haven't uncommented its handler
in app.yaml for a long time; there's little chance it even works as-is
anymore.
Merge branch 'threadsafe' of github.com:hjfreyer/marry-fuck-kill into threadsafe

I accidentally rebased locally. Oh dear.