ensure global brooklyn auto-refresh is respected by get/fetch methods, allowing them to run once but subsequently be noop;
also code comments on desired refactorings; both from code review with @sjcorbett.
also fix bug where effector click sometimes didn't work (two clicks in a row),
and fix bug where "No applications" didn't always display when the tree was emptied (child nodes still present);
and put in a placeholder which can be used for showing a Not Available message after a fade.