resurrect wipe as a post-retraction option

src/mode/fdm/export.js

@@ -207,7 +207,6 @@
                 // console.log({double_retract: zhop});
                 return;
             }
-            // console.log({retract:zhop});
             retracted = retDist;
             moveTo({e:-retracted}, retSpeed, `e-retract ${retDist}`);
             if (zhop) moveTo({z:zpos + zhop}, seekMMM, "z-hop start");

src/mode/fdm/prepare.js

@@ -403,9 +403,13 @@
                         first: slice.index === 0,
                         support: slice.widget.support,
                         onBelt: slice.onbelt,
-                        pretract: () => {
+                        pretract: (wipeDist) => {
                             if (lastLayer && lastLayer.length) {
-                                lastLayer.last().retract = true;
+                                let lastOut = lastLayer.last();
+                                lastOut.retract = true;
+                                if (wipeDist && lastLayer.lastPoly && lastOut.point) {
+                                    print.addOutput(lastLayer, lastOut.point.followTo(lastLayer.lastPoly.center(true), wipeDist));
+                                }
                             }
                         }
                     }