Benchmark corpus: update MooTools.

This is taken from
http://mootools.net/download/get/mootools-core-1.4.5-full-compat.js.

http://code.google.com/p/esprima/issues/detail?id=354
Import esrefactor and its dependencies (estraverse, escope).

This will be used in the identifier highlight demo.

https://code.google.com/p/esprima/issues/detail?id=414
Identifier highlight demo: take the scope into account.

This is done using esrefactor library (which further relies on escope,
another micro library to analyze identifier scope).

https://code.google.com/p/esprima/issues/detail?id=414
Identifier highlight demo: Mention escope and esrefactor.

https://code.google.com/p/esprima/issues/detail?id=414
Merge branch 'master' into gh-pages