457466: popenx() argument mangling hangs python
226766: popen('python -c"...."') tends to hang
Fixes argument quoting in w9xpopen.exe for Windows 9x. w9xpopen.exe
also never attempts to display a MessageBox when not executed
interactively.
Added test_popen() test. This test currently just executes
"python -c ..." as a child process, and checks that the expected
arguments were all recieved correctly by the child process. This
test succeeds for me on Win9x, win2k and Linux, and I hope it does
for other popen supported platforms too :)