Add name of CG

Author: Peter Rushforth

CONTRIBUTING.md

@@ -1,6 +1,6 @@
-# @MapML@
+# Contributing to MapML
 
-This repository is being used for work in the W3C @Maps4HTML@ Community Group, governed by the [W3C Community License Agreement (CLA)](http://www.w3.org/community/about/agreements/cla/). To make substantive contributions, you must join the CG. 
+This repository is being used for work in the [W3C Maps For HTML Community Group](http://www.w3.org/community/maps4html/), governed by the [W3C Community License Agreement (CLA)](http://www.w3.org/community/about/agreements/cla/). To make substantive contributions, you must join the CG. 
 
 If you are not the sole contributor to a contribution (pull request), please identify all 
 contributors in the pull request comment.