Mark TODO as such.
Factor the Tornado application through a WSGI interface.

This commits actually makes *WS slower and in theory less powerful.
It is only a "just-because-we-can-commit", in order to check whether
our current code factors well through a WSGI interface.

Of course this doesn't involve RWS: it is known that RWS doesn't
factor well through a WSGI interface.
Add support for WebService to the gevent-based IO framework.
Migrate AdminWebServer to WebGeventLibrary.

Unfortunately there appear to be problems with Web RPC requests.
Fix Web RPC execution in WebGeventLibrary.

Classes imported from WebAsyncLibrary referenced the wrong
WebService class.
Migrate also ContestWebServer to WebGeventLibrary.

Things mostly work; but we have to eliminate all asynchronous
requests which are not supported via the WSGI interface (and not
required anyway, given that now requests have their nice
dedicated greenlet).