Wipe tower: added an option to change spacing of the lines

src/libslic3r/PrintConfig.cpp

@@ -3150,6 +3150,15 @@ void PrintConfigDef::init_fff_params()
     def->min = 0.;
     def->set_default_value(new ConfigOptionFloat(2.));
 
+    def = this->add("wipe_tower_extra_spacing", coPercent);
+    def->label = L("Wipe tower purge lines spacing");
+    def->tooltip = L("Spacing of purge lines on the wipe tower.");
+    def->sidetext = L("%");
+    def->mode = comExpert;
+    def->min = 100.;
+    def->max = 200.;
+    def->set_default_value(new ConfigOptionPercent(100.));
+
     def = this->add("wipe_into_infill", coBool);
     def->category = L("Wipe options");
     def->label = L("Wipe into this object's infill");