Update README.md

Changed PNG Badges to SVG and Added GoDoc Badge

Author: tcyrus

README.md

@@ -1,8 +1,9 @@
 go-sqlite3
 ==========
 
-[![Build Status](https://travis-ci.org/mattn/go-sqlite3.png?branch=master)](https://travis-ci.org/mattn/go-sqlite3)
-[![Coverage Status](https://coveralls.io/repos/mattn/go-sqlite3/badge.png?branch=master)](https://coveralls.io/r/mattn/go-sqlite3?branch=master)
+[![Build Status](https://travis-ci.org/mattn/go-sqlite3.svg?branch=master)](https://travis-ci.org/mattn/go-sqlite3)
+[![Coverage Status](https://coveralls.io/repos/mattn/go-sqlite3/badge.svg?branch=master)](https://coveralls.io/r/mattn/go-sqlite3?branch=master)
+[![GoDoc](https://godoc.org/github.com/mattn/go-sqlite3?status.svg)](http://godoc.org/github.com/mattn/go-sqlite3)
 
 Description
 -----------