Root of the outline. Captures which code is generated for which model component.
This object also provides access to varioues utilities, such as
error reporting etc, for the convenience of code that builds the outline.
author: Kohsuke Kawaguchi
Gets per-package context information.
This method works for every visible package
(those packages which are supposed to be used by client applications.)
If this grammar doesn't produce anything in the specifiedpackage, return null.