ipython/ipython — pull request #3969 by Carreau (2013-08-09 13:05:10+00:00)
Title: "use strict" in most (if not all) our javascript

+ fix one variable leaking in global nameespace

For more about "strict mode" read [this](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions_and_function_scope/Strict_mode).

TL DR, It's faster, less error prone and more secure.

I made it at "function level" instead of "script level" to allow concatenation with unstrict script.
But I wouldn't mind having it at script level.