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/OBJ.hpp

@@ -0,0 +1,14 @@
+#ifndef slic3r_Format_OBJ_hpp_
+#define slic3r_Format_OBJ_hpp_
+
+namespace Slic3r {
+
+class TriangleMesh;
+class Model;
+
+// Load an OBJ file into a provided model.
+extern bool load_obj(const char *path, Model *model, const char *object_name = nullptr);
+
+}; // namespace Slic3r
+
+#endif /* slic3r_Format_OBJ_hpp_ */