#331 modify EDE behavior for 1st/2nd tier annots

[Brian O.]

Desired EDE behavior for first/second tier annots (according to Lynn):
-open EDE on a second tier annot -> show all annots (as now)
-open EDE on a first tier annot -> only show first-tier annots
(second-tier annots take up a lot of real estate and make it harder to see first-tier annots).

[First tier/second tier is kind of an outdated way to refer to one-level
vs. three-level annots, but what is the desired behavior when opening the
EDE on a gene annot? Show only gene annots, or all first-tier annots,
which include various (one-level) RNAs?]