#100 Collapsible trees for bullet lists

[GregP]

Best done in client-side javascript. Could be relatively
easy to implement with code similar to this:

http://www.mattkruse.com/javascript/mktree/

Trick would be to add simple/easy Wiki markup to
choose which bullets are expanded or collapsed by
default, and perhaps even store list-state in a cookie for
a better user experience.