Commits for Sql authentication

friend module changed name from mysql_auth to sql_auth, take the change into account

factoring out credential changes into a seperate function so that sql_auth_update can use the function transparantly

this creates a new _sql_auth_query() helper function that you can pass
a $query string and a $args array and does the necessary magic to use
the right database

first draft of a sql_auth_update.module that allows one way synchronisation of user/password data to the external database defined in sql_auth