Adds functional test for Stage.init() and changes to non-default namespace for test

Adds a functional test for ensuring that `init()` is run for a stage. Also checks that `failDocumentOnProcessException` works as intended.

Fixes a bug with the cache timeout setting, where it's default value was the wrong constant and it was nested in an extra `getParameter` call.

Changes `FullScaleIT` to use a non-default namespace, and to configuration from code instead of included copy of the resource.properties file. This is debatable - perhaps it would be better to use an Ant task and copy the default configuration to ensure that it can instantiate a working Core. It is not possible to modify a loaded `FileConfiguration`, though, which makes this the only way to have a different namespace without modifying the configuration code.