OFProcess: Correctly handle Unicode env on Win32.
OFApplication: Get Unicode arguments on Win32.

It still stores the normal argc/argv for compatibility, however, the
argument array is created from the Unicode arguments instead.

This also makes -[OFApplication setArgumentCount:andArgumentValues:]
private.
Win32: Allow Unicode filenames in file operations.
OFTCPSocket+SOCKS5: Don't send in native encoding.

There is no standard on which encoding to use for IDNs. Probably, it
would be best to encode them in Punycode before sending them over the
wire, but for now, we just hope the other end understands UTF-8.