Fix: OSProcess on Windows

> I made a small fix for MNU #defaultShellPath, which has been reported a few
> times. I didn't have repo write access, so I committed to
> http://smalltalkhub.com/#!/~SeanDeNigris/SeansOutbox . Sometimes on Windows
> (e.g. seemingly when there are quoted command line arguments), the argument
> to #waitForCommand: and command: must be wrapped in $". I don't think there
> is any harm in always doing this (on Windows), but wanted to get feedback
> from Dave first...
>
> OSProcess-Win32-SeanDeNigris.11
> - Supply shell flags valid for Windows (i.e. '/c'); shell commands via
> PipeableOSProcess are now working, with two restrictions:
> - no access to stdout
> - argument to #waitXyz: may have to be surroundedByDoubleQuotes
>
> OSProcess-Base-SeanDeNigris.41
> - Extract default shell flags ('-c') into a method, so that Windows may
> supply flags valid there (i.e. '/c')
>
> CommandShell-Piping-SeanDeNigris.15
> - Fix Win32 shell by providing path to cmd.exe
>
> HTH