code: function _set_common(stack_name, thing){
  	var ret = null;
  	if( stack_name == 'css_libs' ||
  	    stack_name == 'js_libs' ||
  	    stack_name == 'js_vars' ){
  	    _add_permanently_to(stack_name, thing);
  	    ret = thing;
  	}
  	//console.log('added ' + thing.length + ' to ' + stack_name);
  
  	return ret;
      }
docs: Permanently push an item or a list onto an internal list. Meant for all common variables across pup tent renderings.