Use dictionary.update(complicated.items())

Similar to:
https://github.com/duly/pyjs/commit/311f7c6e706203388c0bc7dea3575cbff060ec92
One (1) test fails in each Python 3.3 and 3.4.
```
Traceback (most recent call last):
  File "test.py", line 77, in test_clean
    combined = dict(simple.items() + complicated.items())
TypeError: unsupported operand type(s) for +: 'dict_items' and 'dict_items'
```