Prevent potential memory leaks with using an Evictor in a container environment.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/pool/trunk@1627004 13f79535-47bb-0310-9956-ffa450edef68
Protect against a user provided eviction policy throwing an exception and stopping the Evictor thread.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/pool/trunk@1627011 13f79535-47bb-0310-9956-ffa450edef68
Use the thread context class loader to load custom eviction policies. This allows application provided eviction policies to be used in a container environment when the pooling implementation is provided by the container.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/pool/trunk@1627022 13f79535-47bb-0310-9956-ffa450edef68