Make the package_as_* methods public so that the methods are detected in Ruby >= 2.0.0 via the respond_to? method.

git-svn-id: https://svn.apache.org/repos/asf/buildr/trunk@1491117 13f79535-47bb-0310-9956-ffa450edef68
Start testing against Ruby 2.0

git-svn-id: https://svn.apache.org/repos/asf/buildr/trunk@1491118 13f79535-47bb-0310-9956-ffa450edef68