add vendor & update README.md

vendor/github.com/mattn/go-isatty/isatty_solaris.go

@@ -0,0 +1,16 @@
+// +build solaris
+// +build !appengine
+
+package isatty
+
+import (
+	"golang.org/x/sys/unix"
+)
+
+// IsTerminal returns true if the given file descriptor is a terminal.
+// see: http://src.illumos.org/source/xref/illumos-gate/usr/src/lib/libbc/libc/gen/common/isatty.c
+func IsTerminal(fd uintptr) bool {
+	var termio unix.Termio
+	err := unix.IoctlSetTermio(int(fd), unix.TCGETA, &termio)
+	return err == nil
+}