1.5.1

This release fixes a bug that causes the bot to crash if it does not find a new Tweet. Replace lines 76-83 with the following, modifying as needed:

            try:
                if alt_replies.index(comic['statuses'][0]['id']) is not ValueError:
                    # This tweet has already been replied to
                    del alt_payload, comic_payload, alt_raw, comic_raw, alt, comic
                    return None # Sleep for 15 seconds
            except ValueError:
                # This tweet has not been replied to
                del alt_payload, comic_payload, alt_raw, comic_raw, alt
                return comic['statuses'][0] # Return comic Tweet