UI: ensure controls list is visible on effect stop

Fixes a small regression introduced by #a4f28e43 where the list
title was not visible if effect was stopped (eg mouse hovered
over list) during fadeout
UI: add comment, tidy up whitespace
UI: allow camera movement within vicinity when following a loc
UI: remove planet client camera#focus_on call

camera#follow will take care of this so it is uneeded
UI: fix/optimize planet spinning

Now spin is consistent for entire duration of effect