def get_default_layout(template, options)
      source_ext = Renderer.source_extension_for(template.source_path)
      options[:layout][source_ext] if options.key?(:layout)
    end
def get_default_layout(template, options)
      source_ext = Renderer.source_extension_for(template.source_path)
      options[:layout][source_ext] if options.key?(:layout)
    end
Gets the default layout that can be specified by the Rogerfile:
 roger.project.options[:renderer][:layout] = {
   "html.erb" => "default"
 }