OB-3087:  Added a new configuration property:
openboxes.fixtures.enabled
This defaults to true if it is not set, which gives the exact same behavior as currently.  However, if you include this property in your configuration with a value of false, it will tell the Bootstrap not to set up test fixtures in the database.  The net result is that starting up the application with a copy of a production or staging database, in development mode, will no longer lead to errors if you include this property in your configuration.