Fix FF 23 console error

docs/intro.md

@@ -1,7 +1,7 @@
 pace
 ====
 
-Include [pace.js](https://raw.github.com/HubSpot/pace/v0.4.8/pace.min.js) and the
+Include [pace.js](https://raw.github.com/HubSpot/pace/v0.4.9/pace.min.js) and the
 [theme](http://github.hubspot.com/pace/docs/welcome/) css of your choice on your page
 (as early as is possible), and you're done!
 

docs/welcome/index.html

@@ -415,7 +415,7 @@ <h2>What is Pace?</h2>
                 <p style="text-align: left">No need to hook into any of your code, progress is detected automatically.</p>
                 <br/>
                 <h2>Download</h2>
-                <p><a class="button" href="https://raw.github.com/HubSpot/pace/v0.4.8/pace.min.js">Pace.js</a></p>
+                <p><a class="button" href="https://raw.github.com/HubSpot/pace/v0.4.9/pace.min.js">Pace.js</a></p>
                 <br/>
                 <h2>Themes</h2>
                 <label class="color-label" for="color-select">Enter a color:</label>

pace.coffee

@@ -202,9 +202,13 @@ _XDomainRequest = window.XDomainRequest
 _WebSocket = window.WebSocket
 
 extendNative = (to, from) ->
-  for key, val of from::
-    if not to[key]? and typeof val isnt 'function'
-      to[key] = val
+  for key of from::
+    try
+      val = from::[key]
+
+      if not to[key]? and typeof val isnt 'function'
+        to[key] = val
+    catch e
 
 # We should only ever instantiate one of these
 class RequestIntercept extends Events