removing references to en-us
Merge pull request #184 from pdehaan/issue-153

removing references to en-us
rename Legal Website.  Fixes #183
rename directory.  fixes #182
Update content of PN

Updates to: job section (to include interns and fellows); opt-out section (to include optimizely opt-out per Bug 100504), title of document, opt-out of email preferences link, addition of "Firefox.com" to web domains, and in-product feedback scenario