update main.lang with {Firefox,Mozilla} on {Facebook,Twitter}

git-svn-id: svn+ssh://svn.mozilla.org/projects/mozilla.com/trunk/locales/he@124407 4eb1ac78-321c-0410-a911-ec516a8615a5
Merge branch 'master' of github.com:MozillaIsrael/mozilla.org-he

git-svn-id: svn+ssh://svn.mozilla.org/projects/mozilla.com/trunk/locales/he@124415 4eb1ac78-321c-0410-a911-ec516a8615a5