prune unnecessary stuff

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

@@ -1,9 +0,0 @@
-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

@@ -1,50 +0,0 @@
-# go-isatty
-
-[![Godoc Reference](https://godoc.org/github.com/mattn/go-isatty?status.svg)](http://godoc.org/github.com/mattn/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)
-[![Go Report Card](https://goreportcard.com/badge/mattn/go-isatty)](https://goreportcard.com/report/mattn/go-isatty)
-
-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