UnicodeDecodeError on Windows

Hello.

When I try to build igo-python on Python 3.3.5 for Windows, UnicodeDecodeError is raised.

```
>python setup.py build
Traceback (most recent call last):
  File "setup.py", line 11, in <module>
    long_description=open('README').read() + "\n\n" + open('CHANGES').read(),
UnicodeDecodeError: 'cp932' codec can't decode byte 0x81 in position 516: illegal multibyte sequence
```