Ported the G-code generator from Perl to C++.

Removed GCode.pm
Removed the Perl bindigns for AvoidCrossingPerimeters, OozePrevention, SpiralVase, Wipe
Changed the std::set of extruder IDs to vector of IDs.
Removed some MSVC compiler warnings, removed obnoxious compiler warnings when compiling the Perl bindings.

xs/xsp/ExtrusionMultiPath.xsp

@@ -16,9 +16,6 @@
     void append(ExtrusionPath* path)
         %code{% THIS->paths.push_back(*path); %};
     double length();
-    bool is_perimeter();
-    bool is_infill();
-    bool is_solid_infill();
     Polygons polygons_covered_by_width();
     Polygons polygons_covered_by_spacing();
     Clone<Polyline> polyline()