[google] gdefine doesn't like an empty resultset

Query: gdefine understeem
ERROR:scripts.ibid-plugin:Exception occured in GoogleScrapeSearch processor of google plugin
Traceback (most recent call last):
  File "scripts/ibid-plugin", line 129, in <module>
    processor.process(event)
  File "./ibid/plugins/__init__.py", line 148, in process
    method(event, *args)
  File "./ibid/plugins/google.py", line 139, in define
    event.addresponse(u' :: '.join(definitions))
TypeError: sequence item 0: expected string or Unicode, NoneType found
Response: I'm not feeling too well

"understeem"? WTF did that come from?

Looks like our scraper was being a bit simplistic. It was returning definition lists like:
[None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None]