Resurrect cpanget as a symlink to cpanspec

- Update the POD in cpanspec to document its use as cpanget
- Subclass Module::Build to create the symlinks to cpanspec and
  cpanspec.1p at build time.

Build.PL

@@ -2,7 +2,22 @@ use strict;
 use warnings;
 use Module::Build;
 
-my $builder = Module::Build->new(
+my $class = Module::Build->subclass(
+    class => 'CpanSpec::Build',
+    code => q{
+        use File::Basename qw(dirname);
+        use FindBin;
+
+        sub ACTION_build {
+            my $self = shift;
+            $self->SUPER::ACTION_build(@_);
+            symlink("cpanspec", "$FindBin::Bin/blib/script/cpanget");
+            symlink("cpanspec.1p", "$FindBin::Bin/blib/bindoc/cpanget.1p");
+        }
+    }
+);
+
+my $builder = $class->new(
     dist_name           => 'cpanspec',
     license             => 'perl',
     dist_author         => 'Steven Pritchard <steve@cpan.org>',