declare some PyCXX functions for export, add PyCXX wrapper for Vector2dPy class

src/Base/GeometryPyCXX.cpp

@@ -108,7 +108,7 @@ Vector2dPy::~Vector2dPy()
 
 void Vector2dPy::init_type(void)
 {
-    behaviors().name( "Vector2dPy" );
+    behaviors().name( "Vector2d" );
     behaviors().doc( "Vector2d class" );
     behaviors().supportGetattro();
     behaviors().supportSetattro();

src/Base/GeometryPyCXX.h

@@ -76,6 +76,8 @@ private:
 
 namespace Py {
 
+typedef PythonClassObject<Base::Vector2dPy> Vector2d;
+
 // Implementing the vector class in the fashion of the PyCXX library.
 class BaseExport Vector : public Object
 {