handle mootools-based apps

[msridhar]

We need to handle sites that use Mootools. This doesn't work currently because Mootools overwrites many built-in JS functions. E.g., this game doesn't work:

http://www.lbnstudio.fr/labs/tetris/test/uTetris/

We need to grab a copy of various built-in functions and then invoke through those pointers. Here's what was done in a previous project:

https://github.com/ecspat/eavesdropper/blob/master/util.js

Not sure if this will be sufficient, but it's probably a good starting point.