Delete redundant translations from localised files.

I used this script:

{{{
#!/usr/bin/env perl
use feature ':5.10';
use strict;
use warnings;
use YAML::Syck qw(Load LoadFile Dump DumpFile);
use File::Slurp qw(slurp);
use Data::Dump 'dump';
use Encode qw(decode);
use autodie;

$YAML::Syck::Headless = 1;
$YAML::Syck::SortKeys = 1;
$YAML::Syck::ImplicitUnicode = 1;

my %lang;
chdir 'locales';
my @yml = glob "*.yml";
my @lang = map { s/\.yml//; $_ } @yml;

for my $lang (@lang) {
    say "Loading $lang";
    $lang{$lang} = LoadFile("$lang.yml")->{$lang};
}

for my $lang (grep { $_ ne 'en' } @lang) {
    while (my ($k, $v) = each %{ $lang{ $lang } }) {
        if ($lang{ $lang }->{$k} eq $lang{ en }->{$k}
            or (exists $lang{ $lang }->{$k} and not exists $lang{ en }->{$k})) {
            delete $lang{ $lang }->{$k};
        }
    }
}

for my $lang (@lang) {
    DumpFile("$lang.yml", { $lang => $lang{$lang} }) or die "arghl";
}
}}}