SLING-4153 - ManagedDC extending from DC, renaming DQueueDistributionStrategy to DQueueDispatchingStrategy

git-svn-id: https://svn.apache.org/repos/asf/sling/trunk@1638734 13f79535-47bb-0310-9956-ffa450edef68
SLING-4143 - add tests for exceptions in error handling scripts, demonstrate current behavior

git-svn-id: https://svn.apache.org/repos/asf/sling/trunk@1638735 13f79535-47bb-0310-9956-ffa450edef68