icons missing in win32 build; won't open a notebook

On 28 June Jaap created the ./icons folder and added some code to widgets.py

if ZIM_DATA_DIR:
 dir = ZIM_DATA_DIR + '../icons'
 for name in ('zim16.png', 'zim32.png', 'zim48.png'):
  file = dir.file(name)
  if file.exists():
   pixbuf = gtk.gdk.pixbuf_new_from_file(file.path)
   iconlist.append(pixbuf)
...

./icons is missing from the Windows build process. Checking in a fix for this, in build_win32.py, shortly.