Parameters now uses a DefaultParametersManager.

The handling of default values for newly created parameters objects is now
delegated to a DefaultParametersManager instance which can either be passed to
the constructor or is dynamically created.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/configuration/trunk@1545825 13f79535-47bb-0310-9956-ffa450edef68