make client internal name be the node alias

We have builtin Drupal core functionality for what we're trying to do in the "internal name" (uname) field of the client object. As things stand, if we change the "client prefix" (a dubious setting in the hosting module), we need to visit and save *every* client node or write a custom PHP script, to update the internal name of all clients.

This is really silly.

Instead, we should create a path alias (path_set_alias in D6, path_save in D7) when we save the node, and only if there's no alias yet. Providing hooks for the pathauto module could also make batch-edition of those nodes a breeze. The API for this is here:

http://drupalcode.org/project/pathauto.git/blob_plain/HEAD:/API.txt