"env" parameter to "popen" won't accept Unicode on Windows - minor Unicode bug

[John Nagle]

I passed a dict for the "env" variable to Popen with Unicode strings
for the dictionary values.

Got:

   File "D:\Python24\lib\subprocess.py", line 706, in _execute_child
		TypeError: environment can only contain strings

It turns out that the strings in the "env" parameter have to be ASCII,
not Unicode, even though Windows fully supports Unicode in CreateProcess.

				John Nagle