PartDesign: refactor positionBySketch

Rename it to positionByPrevious. Rewrite.
Rewrite SketchBased::transformPlacement.

src/Mod/PartDesign/App/FeaturePipe.cpp

@@ -136,7 +136,7 @@ App::DocumentObjectExecReturn *Pipe::execute(void)
  
     try {
         //setup the location
-        this->positionBySketch();
+        this->positionByPrevious();
         TopLoc_Location invObjLoc = this->getLocation().Inverted();
         if(!base.IsNull())
             base.Move(invObjLoc);