Removed some dependencies on Perl IO module.

lib/Slic3r/Test.pm

@@ -7,7 +7,6 @@ require Exporter;
 our @ISA = qw(Exporter);
 our @EXPORT_OK = qw(_eq);
 
-use IO::Scalar;
 use List::Util qw(first);
 use Slic3r::Geometry qw(epsilon X Y Z);
 

t/svg.t

@@ -10,6 +10,7 @@ BEGIN {
 
 use Slic3r;
 use Slic3r::Test;
+use IO::Scalar;
 
 {
     my $print = Slic3r::Test::init_print('20mm_cube');

utils/gcode_sectioncut.pl

@@ -11,7 +11,6 @@ BEGIN {
 }
 
 use Getopt::Long qw(:config no_auto_abbrev);
-use IO::All;
 use List::Util qw(max);
 use Slic3r;
 use Slic3r::Geometry qw(X Y);