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/libslic3r/Format/3mf.hpp

@@ -0,0 +1,19 @@
+#ifndef slic3r_Format_3mf_hpp_
+#define slic3r_Format_3mf_hpp_
+
+namespace Slic3r {
+
+    class Model;
+    class Print;
+    class PresetBundle;
+
+    // Load the content of a 3mf file into the given model and preset bundle.
+    extern bool load_3mf(const char* path, PresetBundle* bundle, Model* model);
+
+    // Save the given model and the config data contained in the given Print into a 3mf file.
+    // The model could be modified during the export process if meshes are not repaired or have no shared vertices
+    extern bool store_3mf(const char* path, Model* model, Print* print, bool export_print_config);
+
+}; // namespace Slic3r
+
+#endif /* slic3r_Format_3mf_hpp_ */