create temporary release branch

git-svn-id: https://svn.apache.org/repos/asf/activemq/activeio/branches/activeio-3.1-temp@644889 13f79535-47bb-0310-9956-ffa450edef68
tree: 289d23a5affbd3a4b701d058f39d76b1c66dfa6a
  1. activeio-core/
  2. LICENSE
  3. NOTICE
  4. pom.xml