Fixed Board.Save, listPcb.py +x and updated TODO.txt

iterator for NETCLASSES (NETCLASS) see class_netclass.h

* Tell swig(somehow) to forget automatic object deletion after adding

  a BOARD_ITEM to BOARD object (it will be automatically deleted by BOARD,

  leading to Segmentation Fault when unloading our python module (double free).

* implement iterator for NETCLASSES (NETCLASS) see class_netclass.h

* add MODULE::Add (see BOARD:Add), to make it more clean

* add wxSize implementation to wx.i and wx helpers (D_PAD uses it)

    def GetTrackWidthList(self):      return self.m_TrackWidthList

    def Save(self,filename):

      return pcbnew.SaveBoard(filename,self)

      return SaveBoard(filename,self)

  }

}

#!/usr/bin/env python

import sys

from pcbnew import *