drop Go versions prior to 1.7 in CI

* drop Go versions prior to 1.7 in CI

* consolidate conn*.go files after dropping old Go support

.travis.yml

@@ -3,9 +3,6 @@ sudo: false
 
 matrix:
   include:
-    - go: 1.4
-    - go: 1.5.x
-    - go: 1.6.x
     - go: 1.7.x
     - go: 1.8.x
     - go: 1.9.x

conn.go

@@ -370,6 +370,15 @@ func (c *Conn) writeFatal(err error) error {
 	return err
 }
 
+func (c *Conn) read(n int) ([]byte, error) {
+	p, err := c.br.Peek(n)
+	if err == io.EOF {
+		err = errUnexpectedEOF
+	}
+	c.br.Discard(len(p))
+	return p, err
+}
+
 func (c *Conn) write(frameType int, deadline time.Time, buf0, buf1 []byte) error {
 	<-c.mu
 	defer func() { c.mu <- true }()

conn_read.go

@@ -1,18 +0,0 @@
-// Copyright 2016 The Gorilla WebSocket Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// +build go1.5
-
-package websocket
-
-import "io"
-
-func (c *Conn) read(n int) ([]byte, error) {
-	p, err := c.br.Peek(n)
-	if err == io.EOF {
-		err = errUnexpectedEOF
-	}
-	c.br.Discard(len(p))
-	return p, err
-}

conn_read_legacy.go

@@ -1,21 +0,0 @@
-// Copyright 2016 The Gorilla WebSocket Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// +build !go1.5
-
-package websocket
-
-import "io"
-
-func (c *Conn) read(n int) ([]byte, error) {
-	p, err := c.br.Peek(n)
-	if err == io.EOF {
-		err = errUnexpectedEOF
-	}
-	if len(p) > 0 {
-		// advance over the bytes just read
-		io.ReadFull(c.br, p)
-	}
-	return p, err
-}