tqdm / tqdm / 2017

Pull #633

travis-ci

Change default for `file` in `tqdm` to sys.stdout

Looking at [_tqdm.py:508](https://github.com/tqdm/tqdm/blob/350640d31/tqdm/_tqdm.py#L508)

Correct description of `file` parameter in `tqdm` should be:

* file  : ``io.TextIOWrapper`` or ``io.StringIO``, optional  
    Specifies where to output the progress messages
    (default: sys.stdout). Uses ``file.write(str)`` and ``file.flush()``
    methods.

I.e.`(default: sys.stdout)` instead of `(default: sys.stderr)`

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