Configuration builders now use the configured BeanHelper instance.

BasicConfigurationBuilder's fetchBeanHelper() was rewritten to obtain a
BeanHelper object from configuration parameters. If one is found, it is used.
Otherwise, the default BeanHelper instance is used. Configuration builders use
the BeanHelper for creating their result configurations. Some builders also
create additional objects dynamically.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/configuration/trunk@1520801 13f79535-47bb-0310-9956-ffa450edef68
Updated changes.xml for [CONFIGURATION-554].

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/configuration/trunk@1520802 13f79535-47bb-0310-9956-ffa450edef68