Update example project settings

The current settings include an error which is fixed here.

The changes:

• Enable debug mode. It's going to be used for development, trying out. So Debug should be enabled by default. (Otherwise accessing Hyperkitty just fails because static files aren't served)
• Fix allowed hosts by adding 127.0.0.1 to the list. the runserver command outputs a link using it, so it should be there by default.
• Put logs inside the example_project directory. Otherwise all commands fail until people create a directory...

I also updated the gitignore for the new log file and added an entry for the virtualenv