Path: added Path.fromShapes and Path.sortWires

* Path.fromShapes can now convert any number of shapes to Path with
optimzied travel distances. It internally uses Path.sortWires to
minimize travel distances, and also sort wires by its Z height in case
of sectioned wires.

* The above python function is impelmented in Path::Area class.

* Path::FeatureShape is rewrote to take advantage of these two
functions.

* Add Path::FeatureAreaView to partially display a Path::FeatureArea's
sections.

src/Mod/Path/App/AreaPy.xml

@@ -58,6 +58,11 @@ any operation</UserDocu>
           </UserDocu>
       </Documentation>
     </Methode>
+    <Methode Name="sortWires" Keyword="true">
+      <Documentation>
+          <UserDocu></UserDocu>
+      </Documentation>
+    </Methode>
     <Methode Name="getParams">
       <Documentation>
         <UserDocu>Get current algorithm parameters as a dictionary.</UserDocu>