WIP: Moved sources int src/, separated most of the source code from Perl.

The XS was left only for the unit / integration tests, and it links
libslic3r only. No wxWidgets are allowed to be used from Perl starting
from now.

src/slic3r/Utils/ASCIIFolding.hpp

@@ -0,0 +1,15 @@
+#ifndef slic3r_ASCIIFolding_hpp_
+#define slic3r_ASCIIFolding_hpp_
+
+#include <string>
+
+namespace Slic3r {
+
+// If possible, remove accents from accented latin characters.
+// This function is useful for generating file names to be processed by legacy firmwares.
+extern std::string fold_utf8_to_ascii(const char *src);
+extern std::string fold_utf8_to_ascii(const std::string &src);
+
+}; // namespace Slic3r
+
+#endif /* slic3r_ASCIIFolding_hpp_ */