C implementation update (address #63)

* Delete defunct RIOT implementation
* Point cn-cbor to jimsch for now

impls.html

@@ -305,13 +305,12 @@ <h2 id="c">C#</h2>
           <p><a class="btn" href="https://github.com/dahomey-technologies/Dahomey.Cbor">View Details »</a></p>
 
           <h2 id="c-c">C, C++</h2>
-          <p>A CBOR implementation in C is part of the RIOT operating system for constrained nodes:</p>
 
-          <p><a class="btn" href="https://github.com/RIOT-OS/RIOT/blob/master/sys/cbor/cbor.c">View Details »</a></p>
+          <p>A C implementation for highly constrained nodes, which achieves
+          a full CBOR decoder in 880 bytes of ARM code (and now also
+          includes an encoder), has been around for a while:</p>
 
-          <p>A C implementation for highly constrained nodes, which achieves a full CBOR decoder in 880 bytes of ARM code (and now also includes an encoder), has recently become available.</p>
-
-          <p><a class="btn" href="https://github.com/cabo/cn-cbor">View Details »</a></p>
+          <p><a class="btn" href="https://github.com/jimsch/cn-cbor">View Details »</a></p>
 
           <p>A basic C++ implementation is also available:</p>