Fix UnicodeDecodeError for `python3 setup.py bdist`

	$ python3.3 setup.py build
	...
	Traceback (most recent call last):
	  File "setup.py", line 60, in <module>
	    long_description=open("README.rst").read(),
	  File "/usr/lib64/python3.3/encodings/ascii.py", line 26, in decode
	    return codecs.ascii_decode(input, self.errors)[0]
	UnicodeDecodeError: 'ascii' codec can't decode byte 0xc3 in position 11646: ordinal not in range(128)

I know that Python3 is unsupported yet, but why not make it easier in the future?