Bugfix: when slicing the same plate multiple times, the results contained old and duplicate data

lib/Slic3r/GUI/Dashboard.pm

@@ -370,6 +370,7 @@ sub export_gcode {
             } else {
                 $print->export_gcode(%params);
             }
+            $print->cleanup;
             Slic3r::GUI::warning_catcher($self)->($_) for @warnings;
         }
         $process_dialog->Destroy;

lib/Slic3r/Print.pm

@@ -60,6 +60,14 @@ sub add_object_from_mesh {
     return $object;
 }
 
+sub cleanup {
+    my $self = shift;
+    $_->cleanup for @{$self->objects};
+    @{$self->skirt} = ();
+    $self->total_extrusion_length(0);
+    $self->processing_time(0);
+}
+
 sub layer_count {
     my $self = shift;
     my $count = 0;

lib/Slic3r/Print/Object.pm

@@ -152,6 +152,11 @@ sub slice {
         if !@{$self->layers};
 }
 
+sub cleanup {
+    my $self = shift;
+    @{$self->layers} = ();
+}
+
 sub detect_surfaces_type {
     my $self = shift;
     Slic3r::debugf "Detecting solid surfaces...\n";