Bulk assessment does not work with Shib users

Users who register by Shibboleth have in the most cases only the one authentication "Shib". Those users are not found when doing bulk assessment.

The called Method

	public List<Identity> getIdentitiesWithLogin(String login) {
		StringBuilder sb = new StringBuilder(256);
		sb.append("select ident from ").append(AuthenticationImpl.class.getName()).append(" as auth")
		  .append(" inner join auth.identity as ident")
		  .append(" inner join ident.user as user")
		  .append(" where lower(auth.authusername)=:login");

in AthenticationDAO does not deliver the correct results because authusername normally is not equal to the identity's name.

Solution: use the same loading mechanism as the one which add members to course or lecture blocks, it search name, nickname, authentication usernames and emails.