Security testing plugin

[dylans]

Based on recent discussions at a conference, there may be interest in adding a security testing extension (e.g. something that takes an app and tests to see if it is susceptible to csrf/xss vulnerabilities, iframe clickjacking, etc.).

This ticket is a place to discuss if it is possible to create a general purpose tool that is useful for JS devs to make sure they've not made any obvious security blunders as part of their testing workflow, and/or make a call to a tool that might do this already.