Cleanup contributor urls in readme. [ci skip]

Author: jdalton

README.md

@@ -89,12 +89,12 @@ info.description; // 'Opera 11.52 (identifying as Firefox 4.0) on Mac OS X 10.7.
 
 ## Author
 
-| [![twitter/jdalton](http://gravatar.com/avatar/299a3d891ff1920b69c364d061007043?s=70)](http://twitter.com/jdalton "Follow @jdalton on Twitter") |
+| [![twitter/jdalton](http://gravatar.com/avatar/299a3d891ff1920b69c364d061007043?s=70)](https://twitter.com/jdalton "Follow @jdalton on Twitter") |
 |---|
 | [John-David Dalton](http://allyoucanleet.com/) |
 
 ## Contributors
 
-| [![twitter/mathias](http://gravatar.com/avatar/24e08a9ea84deb17ae121074d0f17125?s=70)](http://twitter.com/mathias "Follow @mathias on Twitter") |
+| [![twitter/mathias](http://gravatar.com/avatar/24e08a9ea84deb17ae121074d0f17125?s=70)](https://twitter.com/mathias "Follow @mathias on Twitter") |
 |---|
 | [Mathias Bynens](http://mathiasbynens.be/) |