get rid of SVG cache

diff --cc lib/Text/Tradition/Collation.pm
index 5a5edd1,dda8485..f7fb717
--- 1/lib/Text/Tradition/Collation.pm
--- 2/lib/Text/Tradition/Collation.pm
+++ b/lib/Text/Tradition/Collation.pm
@@@ -1039,7 -1064,7 +1047,6 @@@ sub as_graphml 
        map { $gattr_from{$_->name} = 'Collation' } $cmeta->get_all_attributes;
        foreach my $attr ( ( $tmeta->get_all_attributes, $cmeta->get_all_attributes ) ) {
                next if $attr->name =~ /^_/;
--              next if $skipsave{$attr->name};
                next unless $save_types{$attr->type_constraint->name};
                $graph_attributes{$attr->name} = $save_types{$attr->type_constraint->name};
        }
@@@ -1071,7 -1096,7 +1078,6 @@@
      my $rmeta = Text::Tradition::Collation::Reading->meta;
      foreach my $attr( $rmeta->get_all_attributes ) {
                next if $attr->name =~ /^_/;
--              next if $skipsave{$attr->name};
                next unless $save_types{$attr->type_constraint->name};
                $reading_attributes{$attr->name} = $save_types{$attr->type_constraint->name};
        }
@@@ -1101,7 -1126,7 +1107,6 @@@
      my $pmeta = Text::Tradition::Collation::Relationship->meta;
      foreach my $attr( $pmeta->get_all_attributes ) {
                next if $attr->name =~ /^_/;
--              next if $skipsave{$attr->name};
                next unless $save_types{$attr->type_constraint->name};
                $edge_attributes{$attr->name} = $save_types{$attr->type_constraint->name};
        }