Enable non-blocking reads to take place on non-container threads.

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1563206 13f79535-47bb-0310-9956-ffa450edef68
Update to latest DBCP snapshot

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1563213 13f79535-47bb-0310-9956-ffa450edef68