Upgrade Fibers to 1.0.0 and UglifyJS to 2.2.3.

This definitely won't "work" because both have API changes.

UglifyJS 1 was having issues minifying certain code (eg lodash).  But UglifyJS 2
was occasionally segfaulting (as was other code using large regexps).  See the
bottom of laverdet/node-fibers#89

Hopefully this will fix it.

client/concepts.html

@@ -641,7 +641,7 @@ <h3 class="nosection">Running on your own infrastructure</h3>
 
     $ cd bundle/server/node_modules
     $ rm -r fibers
-    $ npm install fibers@0.6.9
+    $ npm install fibers@1.0.0
 {{/warning}}
 
 {{/better_markdown}}