Added "real" get_current_revision

lib/SugarTrail/Repo.pm

     $master->{text} = $self->load_text($args->{source})
         or return;
     $master->{source} = $args->{source};
+    $master->{revision} = $self->get_revision($args->{source});
 
     return $master;
 }

lib/SugarTrail/Repo/Filesystem.pm

     return $self->{root} . $source;
 }
 
+sub get_revision {
+    my $self = shift;
+    my $source = shift // $self->{source};
+    my $file = $self->_get_filename($source);
+    return (stat($file))[9];  # 9 = mtime
+}
+
 sub load_text {
     my $self = shift;
     my $source = shift;

lib/SugarTrail/Template/Master.pm

     }
 
     $slave->{meta}->{'Master'} = $self->{source};
-    $slave->{meta}->{'Master Revision'} = $self->get_current_revision();
+    $slave->{meta}->{'Master Revision'} = $self->{revision};
     $slave->{meta}->{'Params'} = mkmymime($args);
 
     $slave->{steps} = \@slave_steps;
     return $slave;
 }
 
-# skel: returns time (might be useful in absence of VCS)
-sub get_current_revision {
-    return time;
-}
-
 sub mkmymime {
     my $d = shift;
     my $d1 = "; "; my $d2 = "=";