*Title: Impoved updating process of the 'eZURLAlias'es

*Original author: Bard Farstad

*Documentation:
A small patch which allows to update the URL alias children only when  
actually needed on publishing. This increases publishing performance  
in first time publishing - which is the most common case. On large  
sites (nx100k of objects) you get significant speed boost on  
publishing in these cases.
