Part: changes to Part Module

* Added Part::Feature::getTopoShape/getShape() function that can obtain
  shape from any object with proper implementation of getSubObject(). It
  can even construct compound from group object with proper implementation
  of getSubObjects().

* Modified ViewProviderExt to work on any object, because it now obtain
  the shape using Part::Feature::getShape()

* Modified various Part features to obtain base/tool shapes using
  Part::getShape(), which allows them to be any type of object,
  including Link and groups.

* Modified various Part command to relax type requirement on selected
  objects.

* Add support of link and group to dimension, and add dimension refresh
  command

* Support link and group in simple command command, and add a few more
  copy command variations.

* Add special handling of 'Shape' attribute in PropertyContainerPy and
  use Part::Feature::getShape() to return shape for any object without
  Shape property. This allows many python feature work with any object
  without modification.

* GeometrySurface/CurvePy, add convenience attribute 'Rotation'

* TopoShapePy:

    * Extended support of sub shape attribute, e.g. Compound1, Solid2,
      SubShape3 ('SubShape' is used to access child shape of a compound)

    * makeWires(), new API to sort and return wires given a list of edges.

    * transformed/translated/rotated/scaled(), return a new shape with
      some transformation.

    * findPlane(), find the plane of a planar shape

    * isCoplanar(), check if two shape are coplanar

src/Mod/Part/App/FeaturePartCommon.cpp

@@ -89,9 +89,7 @@ App::DocumentObjectExecReturn *MultiCommon::execute(void)
 
     std::vector<App::DocumentObject*>::iterator it;
     for (it = obj.begin(); it != obj.end(); ++it) {
-        if ((*it)->getTypeId().isDerivedFrom(Part::Feature::getClassTypeId())) {
-            s.push_back(static_cast<Part::Feature*>(*it)->Shape.getValue());
-        }
+        s.push_back(Feature::getShape(*it));
     }
 
     bool argumentsAreInCompound = false;