Experimental support for `batch` under MsWindows

2) I prepare two executable (4K each,i.e, the smallest size possible
    under Windows): (i) a 'windowed' application (rconsole.exe) which should
    behaves like my current version and (ii) a 'console' (I suppose
    that a better name for rconsole is needed) application
    (rbatch.exe) which does not open a graphich console but
    use 'stdio'. I didn't test Emacs+ESS since, after some
    bad (but old) experiences, I use Emacs
    only under Unix; however, at least, `rbatch < afile > anothefile'
    seems to work; in addition, when isatty() is false (I expect
    this happening under Emacs) the code is exactly the Unix one.
    
I hope someone would test this version since, if it works,
I think that can add something to the current one (in particular,
if starting from this version we can obtaning an executable
working under Emacs).
But be aware: (i) it is the result of 2 hour of works on a train;
                                                      ~~~~~~~~~~
(ii) I have only test it on a Win98 notebook; (iii) as
Luke said, rbatch should not work under Win32s; (iv) Brian's
libraries must be rebuilt to make them working with this version.