Added functionality to Config to allow overriding local.conf with a spec...

...ified conf file

The system property name is: local.conf.override and can be found in the Config object as a constant. It is the pointer to where the overriden file is to be found. It can be an absolute or relative path.
should probably call this local.conf.location or something, as it's just an artefact of the history that we class it as an override, actually it's just a value, and the default happens to be "./local.conf"