wip: invite a friend registration
Merge branch 'master' into feature/friendinvite
Merge remote-tracking branch 'origin/master' into feature/friendinvite
friend invite wip
invite wip
wip: coded rudimentary invite a friend UI on question page

TODO: make this into a directive and make it pretty
Merge branch 'master' into feature/friendinvite
invitefriend: overlay ui.
invitefriend: now working.