Expose method to Python to get property name of main geometry

fix inheritance of MeshFeaturePy
fix inheritance of PartFeaturePy
remove useless test() method
implement getPyObject in GeoFeature in case a sub-class doesn't implement it

src/Mod/Part/App/PartFeaturePy.xml

@@ -1,22 +1,17 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <GenerateModel xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="generateMetaModel_Module.xsd">
   <PythonExport 
-    Father="DocumentObjectPy"  
+    Father="GeoFeaturePy"
     Name="PartFeaturePy" 
     Twin="Feature" 
     TwinPointer="Feature" 
     Include="Mod/Part/App/PartFeature.h" 
     Namespace="Part" 
-    FatherInclude="App/DocumentObjectPy.h" 
+    FatherInclude="App/GeoFeaturePy.h"
     FatherNamespace="App">
     <Documentation>
       <Author Licence="LGPL" Name="Juergen Riegel" EMail="FreeCAD@juergen-riegel.net" />
       <UserDocu>This is the father of all shape object classes</UserDocu>
     </Documentation>
-    <Methode Name="test">
-            <Documentation>
-                    <UserDocu>test</UserDocu>
-            </Documentation>
-    </Methode>
   </PythonExport>
 </GenerateModel>