Updated test

xs/t/20_print.t

@@ -7,7 +7,7 @@ use Slic3r::XS;
 use Test::More tests => 5;
 
 {
-    my $print = Slic3r::Print->_new;
+    my $print = Slic3r::Print->new;
     isa_ok $print, 'Slic3r::Print';
     isa_ok $print->config, 'Slic3r::Config::Print::Ref';
     isa_ok $print->default_object_config, 'Slic3r::Config::PrintObject::Ref';