feat: better badge (#246)

* feat: adds better badge

* uses svg badge on README

* adds badge md code

* fallback to Helvetica

Author: alanshaw

README.md

@@ -39,7 +39,11 @@ Send in a PR if you find or write one!
 
 Include this badge in your readme if you make a new module that implements interface-ipfs-core API.
 
-![](/img/badge.png)
+![](/img/badge.svg)
+
+```md
+[![IPFS Core API Compatible](https://cdn.rawgit.com/ipfs/interface-ipfs-core/master/img/badge.svg)](https://github.com/ipfs/interface-ipfs-core)
+```
 
 ## Install