Make Edge Selection Area Adjustable

- Edges may be difficult to select depending on drawing
  scale and zoom level.
- Parameter: Preferences/Mod/TechDraw/General/EdgeFuzz

src/Mod/TechDraw/Gui/QGIEdge.cpp

@@ -93,6 +93,15 @@ Qt::PenStyle QGIEdge::getHiddenStyle()
     return hidStyle;
 }
 
+ double QGIEdge::getEdgeFuzz(void) const
+{
+    Base::Reference<ParameterGrp> hGrp = App::GetApplication().GetUserParameter().GetGroup("BaseApp")->
+                                         GetGroup("Preferences")->GetGroup("Mod/TechDraw/General");
+    double result = hGrp->GetFloat("EdgeFuzz",10.0);
+    return result;
+}
+
+
 QRectF QGIEdge::boundingRect() const
 {
     return shape().controlPointRect();
@@ -102,7 +111,7 @@ QPainterPath QGIEdge::shape() const
 {
     QPainterPath outline;
     QPainterPathStroker stroker;
-    stroker.setWidth(2.0);
+    stroker.setWidth(getEdgeFuzz());
     outline = stroker.createStroke(path());
     return outline;
 }
@@ -111,5 +120,7 @@ void QGIEdge::paint ( QPainter * painter, const QStyleOptionGraphicsItem * optio
     QStyleOptionGraphicsItem myOption(*option);
     myOption.state &= ~QStyle::State_Selected;
 
+    //~ painter->drawRect(boundingRect());          //good for debugging
+
     QGIPrimPath::paint (painter, &myOption, widget);
 }

src/Mod/TechDraw/Gui/QGIEdge.h

@@ -49,6 +49,8 @@ public:
     void setSmoothEdge(bool b) { isSmoothEdge = b; }
     bool getSmoothEdge() { return(isSmoothEdge); }
     virtual void setPrettyNormal() override;
+    
+    double getEdgeFuzz(void) const;
 
 protected:
     int projIndex;                                                     //index of edge in Projection. must exist.