pythonw in py3k sets std{in,out,err} to None...
pythonw in py3k sets std{in,out,err} to None
The print statement works without error, even though the stdio file objects are instances
of None. Since they are instances of None, however, the encoding attribute will not
exist, so protect blind attribute access of std{in,out,err} by using a new function, get_stream_enc.
