ACE-362 Updated the readme file.

git-svn-id: https://svn.apache.org/repos/asf/ace/trunk@1586374 13f79535-47bb-0310-9956-ffa450edef68
Updated the readme to reflect the new Eclipse/Java version we use.

git-svn-id: https://svn.apache.org/repos/asf/ace/trunk@1586375 13f79535-47bb-0310-9956-ffa450edef68