Minor SimulationLog safety checks
minor clarity
clean up the postgres startup scripts somewhat; 'init.sh' installs the replication hooks for you

So now, installing this system should look something like

Get the software
$ pkg_add postgres python-psycopg2 python-sqlalchemy
$ git clone modex
$ cd modex/

Set up the DB
$ cd src/backend/db
$ ./init.sh eutopia #or other model of your choice
$ ./server.sh

in a different session, set up the simulation
$ cd src/backend/models/eutopia
$ ./eutopia postgresql://localhost/eutopia  #but you can use "sqlite:///eutopia.sqlite" if you are having problems with postgres

in a third and fpurth and fifth session, set up the web clients
$ python -m SimpleHTTPServer
$ cd src/backend/db; ./replicate_server 8081 postgresql://localhost/eutopia activity_counts #<-- this part is still dodgy
$ browser http://localhost:8000/src/frontend/demo.html

AND IF THIS DOESN'T WORK AS PROMISED IT'S A BUG