New XS framework for C and C++ code

xs/t/01_trianglemesh.t

@@ -0,0 +1,12 @@
+#!/usr/bin/perl
+
+use strict;
+use warnings;
+
+use Slic3r::XS;
+use Test::More tests => 1;
+
+is Slic3r::TriangleMesh::XS::hello_world(), 'Hello world!',
+    'hello world';
+
+__END__