Add travis-ci integration

Author: Tarmigan Casebolt

.travis.yml

@@ -0,0 +1,9 @@
+language: go
+go:
+  - 1.4
+  - 1.6
+  - tip
+env:
+  - GOOS=linux CGO=1
+  - GOOS=linux CGO=0
+  - GOOS=windows GOARCH=386

README.md

@@ -1,4 +1,5 @@
 [![GoDoc](https://godoc.org/github.com/tarm/serial?status.svg)](http://godoc.org/github.com/tarm/serial)
+[![Build Status](https://travis-ci.org/tarm/serial.svg?branch=master)](https://travis-ci.org/tarm/serial)
 
 Serial
 ========

basic_test.go

@@ -3,13 +3,19 @@
 package serial
 
 import (
+	"os"
 	"testing"
 	"time"
 )
 
 func TestConnection(t *testing.T) {
-	c0 := &Config{Name: "/dev/ttyUSB0", Baud: 115200}
-	c1 := &Config{Name: "/dev/ttyUSB1", Baud: 115200}
+	port0 := os.Getenv("PORT0")
+	port1 := os.Getenv("PORT1")
+	if port0 == "" || port1 == "" {
+		t.Skip("Skipping test because PORT0 or PORT1 environment variable is not set")
+	}
+	c0 := &Config{Name: port0, Baud: 115200}
+	c1 := &Config{Name: port1, Baud: 115200}
 
 	s1, err := OpenPort(c0)
 	if err != nil {