Added note on hiding the written date

Hiding the explicit written date (e.g. Sun, 25 Nov 18), is now easy. Just go to the correct section of thie function and uncomment the lines, as suggested in the details of the function.

Calendar/stable.py

@@ -139,6 +139,7 @@ def main():
                 pass
 
             """Drawing today's date at the top left corner"""
+            """Uncomment this section (the following 5 lines) to hide date at top left corner"""
             space1=Image.new('1', (115,25), color=255)
             date = ImageDraw.Draw(space1)
             date.text((2, 3), (time.strftime('%a %-d %b %y')),  font=font, fill=0)