On Travis-CI worker, this test raises EAFNOSUPPORT instead of EADDRINUSE. This change is for checking from where the exception raised.
I don't want put a pressure on supporting it because 1.9 mode works fine.
On Windows, calling File#size fails with an Unknown error (20047). This workaround uses File#lstat instead.
open-uri modifies the behavior of global open(), which is undesirable in some situations. Do not require it unless it is going to be used.
It raised 'premature end of regular expression' if debug_dev is set, $KCODE is not 'n' and on 1.8. Closes #74.