Added new example to index.html

examples/graph2d/index.html

@@ -24,6 +24,7 @@
   <p><a href="15_streaming_data.html">15_streaming_data.html</a></p>
   <p><a href="16_bothAxis_titles.html">16_bothAxis_titles.html</a></p>
   <p><a href="17_dynamicStyling.html">17_dynamicStyling.html</a></p>
+  <p><a href="18_scatterplot.html">18_scatterplot.html</a></p>
 
 </div>
 </body>