add namespaces to config module

[progrium]

Right now, config loads into a global registry. But it should namespace these configurations.

Also, there is a Namespace class used by load() now that is used for making sub configuration namespaces... it has nothing to do with this issue. Perhaps that should be renamed. Or maybe this should be called something else.

[progrium]

Configuration is now (0.5.0) loaded into a Config object, which represents one configuration. If you have two configurations (say for testing two apps in one process) you can create two Config objects and pass them into two Process objects.