Update pom task to support Maven Central requirements

[micha]

@daveyarwood reports that the Maven Central Requirements are not fully supported yet.

For example, it was necessary to add a <developers> block to the POM:

<developers>
  <developer>
    <id>daveyarwood</id>
    <name>Dave Yarwood</name>
    <email>dave.yarwood@gmail.com</email>
    <url>http://daveyarwood.github.io</url>
    <roles>
      <role>packager</role>
    </roles>
    <timezone>America/New_York</timezone>
    <properties>
      <picUrl>http://daveyarwood.github.io/assets/themes/emptyorchestra/dave.jpg</picUrl>
    </properties>
  </developer>
</developers>