Remove outdated comment about copying syn.js into repo. No longer the case.

test/core_tests_presentation.html

@@ -17,7 +17,6 @@
     <div class="step" id="fourth" data-x="-400" data-y="0">Fourth slide</div>
   </div>
   <script src="../js/impress.js"></script>
-  <!-- This is a copy of dist/syn.js from bower install syn. (The one in npm install doesn't work in a browser.) -->
   <!-- See http://bitovi.com/blog/2010/07/syn-a-standalone-synthetic-event-library.html for simple usage guide. -->
   <script src="../node_modules/syn/dist/global/syn.js"></script>
 </body>