merging concurrency-utilities-ee module with openejb-core

git-svn-id: https://svn.apache.org/repos/asf/tomee/tomee/trunk@1608091 13f79535-47bb-0310-9956-ffa450edef68
sharing push/pop context for tasks in another thread instead of having it 3 times (main goal of important concurrency utilities)

git-svn-id: https://svn.apache.org/repos/asf/tomee/tomee/trunk@1608094 13f79535-47bb-0310-9956-ffa450edef68