b3 configuration to mirror emf artifacts for maven

emf.b3aggr

<?xml version="1.0" encoding="UTF-8"?>
<aggregator:Aggregation xmi:version="2.0" xmlns:xmi="http://www.omg.org/XMI" xmlns:aggregator="http://www.eclipse.org/b3/2011/aggregator/1.1.0" label="emf" packedStrategy="SKIP" mavenResult="true">
  <validationSets label="emf">
    <contributions label="juno">
      <repositories location="http://download.eclipse.org/releases/juno/">
        <features name="org.eclipse.xsd.sdk.feature.group"/>
        <features name="org.eclipse.xsd.source.feature.group"/>
      </repositories>
    </contributions>
  </validationSets>
  <configurations operatingSystem="linux" windowSystem="gtk" architecture="x86_64"/>
</aggregator:Aggregation>