Removed some obsolete Perl bindings.

Removed libslic3r from the default include paths for all modules but
libslic3r. Now headers from libslic3r need to be included with an
explicit path (libslic3r/libslic3r.h etc)
Split the localization macros into I18N.{cpp,h}

src/slic3r/GUI/PresetHints.cpp

@@ -1,15 +1,16 @@
-//#undef NDEBUG
 #include <cassert>
 
+#include "libslic3r/Flow.hpp"
+#include "libslic3r/libslic3r.h"
+
 #include "PresetBundle.hpp"
 #include "PresetHints.hpp"
-#include "Flow.hpp"
 
 #include <boost/algorithm/string/predicate.hpp>
 #include <wx/intl.h> 
 
-#include "../../libslic3r/libslic3r.h"
 #include "GUI.hpp"
+#include "I18N.hpp"
 
 namespace Slic3r {