readme: use svg build status

fb55 · fb55 · commit 907e493fd1b3 · 2015-01-23T00:32:31.000+01:00
looked horrible on retina screens -.-
diff --git a/readme.md b/readme.md
@@ -1,4 +1,4 @@
-#CSSwhat [![Build Status](https://secure.travis-ci.org/fb55/CSSwhat.png?branch=master)](http://travis-ci.org/fb55/CSSwhat)
+#CSSwhat [![Build Status](https://secure.travis-ci.org/fb55/CSSwhat.svg?branch=master)](http://travis-ci.org/fb55/CSSwhat)
 
 a CSS selector parser
 

Original file line number	Diff line number	Diff line change
`@@ -1,4 +1,4 @@`
`1`		`-#CSSwhat [![Build Status](https://secure.travis-ci.org/fb55/CSSwhat.png?branch=master)](http://travis-ci.org/fb55/CSSwhat)`
	`1`	`+#CSSwhat [![Build Status](https://secure.travis-ci.org/fb55/CSSwhat.svg?branch=master)](http://travis-ci.org/fb55/CSSwhat)`
`2`	`2`
`3`	`3`	`a CSS selector parser`
`4`	`4`