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/GUI/PresetHints.hpp

@@ -0,0 +1,30 @@
+#ifndef slic3r_PresetHints_hpp_
+#define slic3r_PresetHints_hpp_
+
+#include <string>
+
+#include "PresetBundle.hpp"
+
+namespace Slic3r {
+
+// GUI utility functions to produce hint messages from the current profile.
+class PresetHints
+{
+public:
+    // Produce a textual description of the cooling logic of a currently active filament.
+    static std::string cooling_description(const Preset &preset);
+    
+    // Produce a textual description of the maximum flow achived for the current configuration
+    // (the current printer, filament and print settigns).
+    // This description will be useful for getting a gut feeling for the maximum volumetric
+    // print speed achievable with the extruder.
+    static std::string maximum_volumetric_flow_description(const PresetBundle &preset_bundle);
+
+    // Produce a textual description of a recommended thin wall thickness
+    // from the provided number of perimeters and the external / internal perimeter width.
+    static std::string recommended_thin_wall_thickness(const PresetBundle &preset_bundle);
+};
+
+} // namespace Slic3r
+
+#endif /* slic3r_PresetHints_hpp_ */