Add blockdelete.pl for mass block/delete of recent vandalisms

blockdelete.pl scans recent changes, finds suspicious new pages created by
anons and for each page deletes it and blocks the author for 1 day.

Technically new: uses Term::ANSIColor and MediaWiki::API for block/delete.

Also updates Util.pm to croak when trying to load_hash() from
a non-existent file.