fbio.bi IsRedirected(): Default to checking stdout

instead of checking stdin by default - seems more logical & more commonly
needed.

Author: dkl

inc/fbio.bi

@@ -1,3 +1,5 @@
 #pragma once
 
-declare function IsRedirected alias "fb_IsRedirected"(byval is_input as long = -1) as long
+'' IsRedirected(FALSE) = check stdout
+'' IsRedirected(TRUE) = check stdin
+declare function IsRedirected alias "fb_IsRedirected"(byval is_input as long = 0) as long