Modified the weird config/install scripts a little.

Basically tools/install_stochkit.sh writes
conf/config which is opened by
conf/stochss-env.py which writes another config file
app/conf/app_config.py which is read by
app/stochssapp.py when launched by
launchapp (if this is not called, conf/stochss-env.py is never called)

This sort of confused configuration is necessary to support a user defined Stochkit. Ideally, if they don't run tools/install_stochkit.sh, a Stochkit can be detected from the environmental variable STOCHKIT_HOME. It is not possible to just check environmental variables from within a Google appengine code as far as we can tell: os.environ gets overwritten.

Even though these scripts run every time at launch of the application, if the user using the application has already logged in, that users settings are cached from the first time these scripts were run.

So don't make changes to conf/config or any of these files and expect them to propagate to the webapp on anything but the first launch