Move the admin menu hook into a separate file

In Drupal 6, the admin menu hooks functions are normally put into a file that in this case should be named smileys.admin.inc. This is made possible by a new menu attribute (file) which permits Drupal to know in which file the menu hook function is located.
The purpose of this is to reduce the code that is parsed by the PHP interpreter (therefore, the load of the server), and which would never be executed in some circumstances; that is particularly true for the administration pages, which are showed only when a restricted number of users click on a navigation menu. It also makes the module more modular (and that is not a bad thing also).

Considering that all this is handled automatically by Drupal, there aren't any excuses to not use this feature.