windows and node 0.10 support (closes #4 and #8)

[davidmarkclements]

1. Windows has no /dev/stdin
2. process.stdin.fd however already contains the STDIN fd (0) on all platforms
3. fs.readSync(process.stdin.fd, 'rs') works on Windows, on Node v0.10+
4. fs.readSync(process.stdin.fd, 'rs') works on non-windows on Node 0.12+ (at least tested on OS X)
5. reading from /dev/stdin on v0.10 on non-windows fails also (at least on OS X)
6. reading from /dev/tty WORKS on 0.10 on non-windows

So,

if v0.12+ OR windows we read from process.stdin.fd if < 0.12 AND NOT windows we read from /dev/tty

Note: Edge case - will fail in REPL in windows (EBADF)