added the acs_user::get_by_username proc and the permanent switch to acs_user::delete that serves as a wrapper around the acs_user.delete plsql proc. Unfortunately that proc doesn't seem to work reliably
making the auth_authentication test case pass. Fixing a few bugs and adding some error handling to the authentication proc. Simon has added other test cases that have not been finished yet
defaulting username of site-wide-admin to email and making sure the stubbed ad_conn can handle multiple arguments (create-admin-2 bombed before this fix)