use env for all .perl files in regression test directory

regression-testing/compare-results.perl

@@ -1,7 +1,8 @@
-#!/usr/bin/perl -w
+#!/usr/bin/env perl
 
 # $Id$
 
+use warnings;
 use strict;
 my ($results, $truth) = @ARGV;
 

regression-testing/ensure-regression-data-here.perl

@@ -1,5 +1,6 @@
 #!/usr/bin/env perl
 # downloads the regression data
+use warnings;
 use strict;
 use MosesRegressionTesting;
 

regression-testing/run-single-test.perl

@@ -1,7 +1,8 @@
-#!/usr/bin/perl -w
+#!/usr/bin/env perl
 
 # $Id$
 
+use warnings;
 use strict;
 my $script_dir; BEGIN { use Cwd qw/ abs_path /; use File::Basename; $script_dir = dirname(abs_path($0)); push @INC, $script_dir; }
 use MosesRegressionTesting;

regression-testing/run-test-detokenizer.perl

@@ -1,8 +1,9 @@
-#!/usr/bin/perl -w
+#!/usr/bin/env perl
 #
 # Detokenization tests.
 #
 
+use warnings;
 use strict;
 # This is here to suppress (false) warnings about OLDOUT and OLDERR being used only once.  Maybe there is a less brutish way to suppress that, but I don't know it.
 no warnings 'once';

regression-testing/run-test-extract.perl

@@ -1,5 +1,6 @@
-#!/usr/bin/perl -w
+#!/usr/bin/env perl
 
+use warnings;
 use strict;
 
 BEGIN {

regression-testing/run-test-mert.perl

@@ -1,5 +1,6 @@
-#!/usr/bin/perl -w
+#!/usr/bin/env perl
 
+use warnings;
 use strict;
 my $script_dir; BEGIN { use Cwd qw/ abs_path /; use File::Basename; $script_dir = dirname(abs_path($0)); push @INC, $script_dir; }
 #use MertRegressionTesting;

regression-testing/run-test-misc.perl

@@ -1,5 +1,6 @@
-#!/usr/bin/perl -w
+#!/usr/bin/env perl
 
+use warnings;
 use strict;
 
 BEGIN {

regression-testing/run-test-scorer.perl

@@ -1,5 +1,6 @@
-#!/usr/bin/perl -w
+#!/usr/bin/env perl
 
+use warnings;
 use strict;
 
 BEGIN {