#71 use stdin not only on tty

[Stas Sergeev]

Currently vde_switch uses isatty()
checks for stdin, and ignores stdin
otherwise. But it should be possible
to run vde_switch with pipe being used
for stdin, and EOF from pipe should be
handled.

The attached patch removes the isatty()
checks.

[renzo davoli]

Patch applied both in trunk and rd235 experimental version. tnx.