Code coverage test added.

.travis.yml

@@ -4,7 +4,6 @@ install:
   - go get -d -t -v ./... && go build -v ./...
 
 go:
-  - 1.5
   - 1.6
   - 1.7
   - tip

README.md

@@ -2,8 +2,11 @@
 
 # Excelize
 
-[![Build Status](https://godoc.org/github.com/Luxurioust/excelize?status.svg)](https://godoc.org/github.com/Luxurioust/excelize)
-[![Build Status](https://img.shields.io/badge/license-bsd-orange.svg)](https://opensource.org/licenses/BSD-3-Clause)
+[![Build Status](https://travis-ci.org/Luxurioust/excelize.svg?branch=master)](https://travis-ci.org/Luxurioust/excelize)
+[![Code Coverage](https://codecov.io/gh/Luxurioust/excelize/branch/master/graph/badge.svg)](https://codecov.io/gh/Luxurioust/excelize)
+[![GoDoc](https://godoc.org/github.com/Luxurioust/excelize?status.svg)](https://godoc.org/github.com/Luxurioust/excelize)
+[![Licenses](https://img.shields.io/badge/license-bsd-orange.svg)](https://opensource.org/licenses/BSD-3-Clause)
+[![Join the chat at https://gitter.im/xuri-excelize/Lobby](https://img.shields.io/badge/GITTER-join%20chat-green.svg)](https://gitter.im/xuri-excelize/Lobby)
  
 ## Introduction