googleTrends addition

Let me know if there are some changes that should be done, I am testing this my self now and it at least has run two days in a row for me.
1. this is equivalent to ```queries - history```. See [doc](https://docs.python.org/2/library/sets.html#set-objects)
2. If you were to rewrite that line in accordance with 1, you would notice that it must return a new set, as it in fact is said in the same doc. So, that line doesn't make any sense.

What you should do, since it's a mutable set is discussed further in the same doc. Long story short:
```
queries.difference_update(history)
# which is equivalent of
queries -= history
```

The same is applied to line 73 as well