Use mod vendor for vendored directory (backwards compatible)

vendor/github.com/mattn/go-isatty/.travis.yml

@@ -0,0 +1,8 @@
+language: go
+go:
+  - tip
+before_install:
+  - go get github.com/mattn/goveralls
+  - go get golang.org/x/tools/cmd/cover
+script:
+    - $HOME/gopath/bin/goveralls -repotoken 3gHdORO5k5ziZcWMBxnd9LrMZaJs8m9x5

vendor/github.com/mattn/go-isatty/README.md

@@ -0,0 +1,47 @@
+# go-isatty
+
+[![Build Status](https://travis-ci.org/mattn/go-isatty.svg?branch=master)](https://travis-ci.org/mattn/go-isatty) [![Coverage Status](https://coveralls.io/repos/github/mattn/go-isatty/badge.svg?branch=master)](https://coveralls.io/github/mattn/go-isatty?branch=master)
+
+isatty for golang
+
+## Usage
+
+```go
+package main
+
+import (
+	"fmt"
+	"github.com/mattn/go-isatty"
+	"os"
+)
+
+func main() {
+	if isatty.IsTerminal(os.Stdout.Fd()) {
+		fmt.Println("Is Terminal")
+	} else if isatty.IsCygwinTerminal(os.Stdout.Fd()) {
+		fmt.Println("Is Cygwin/MSYS2 Terminal")
+	} else {
+		fmt.Println("Is Not Terminal")
+	}
+}
+```
+
+## Installation
+
+```
+$ go get github.com/mattn/go-isatty
+```
+
+## License
+
+MIT
+
+## Author
+
+Yasuhiro Matsumoto (a.k.a mattn)
+
+## Thanks
+
+* k-takata: base idea for IsCygwinTerminal
+
+    https://github.com/k-takata/go-iscygpty