Sketcher: New Feature: Symmetric tool

=====================================

Creates geometry symmetric to the selected one with respect to the last selected point or line.

It does not support the following constraints:

- Angle
- Horiz/vertical distance
- SnellLaw

Horizontal and Vertical (directional) dimensions removed from the the copying process when created
on a single edge (by picking one edge instead of two points), i.e. Constraint involving only one GeoId at "First".

src/Mod/Sketcher/App/SketchObjectPy.xml

@@ -132,6 +132,11 @@
         <UserDocu>trim a curve with a given id at a given reference point</UserDocu>
       </Documentation>
     </Methode>
+    <Methode Name="addSymmetric">
+      <Documentation>
+        <UserDocu>add a symmetric geometric objects to the sketch with respect to a reference point or line</UserDocu>
+      </Documentation>
+    </Methode>    
     <Methode Name="ExposeInternalGeometry">
       <Documentation>
         <UserDocu>Exposes all internal geometry of an object supporting internal geometry</UserDocu>