'Create a tarball with the tool\'s xml, help images, and test data.
:param trans: the web transaction
:param tool_id: the tool ID from app.toolbox
:returns: tuple of tarball filename, success True/False, message/None'

def package_tool(self, trans, tool_id):

    if (tool_id not in self._tools_by_id):
        raise ObjectNotFound(("No    tool    found    with    id    '%s'." % escape(tool_id)))
    else:
        tool = self._tools_by_id[tool_id]
        return tool.to_archive()
