Candidate patch for multilevel_visibility_monitor.
First cut at integrating multilevel_visibility_monitor into contacts app.
Return monitor handle.
Add monitor.ignore() to allow DOM changes without mutation observer overhead.
Render contact using monitor.ignore()
Use maxDepth=3 with visibility monitor.
Coalesce multiple renders in nextTick to reduce scroll jank.
Optimize renderOrg for normal contact path.
Fix display of letter section headers.
Make sure the group title is shown when contacts are added.
Fix clicking on contacts in list.  ID must be provided in order to set data-uuid.
Free loaded contacts after we render them.  No need to keep them around.
Remove debug.
Update visibility_monitor with pause/resume and remove hacked in ignore().
Use monitor pause/resume instead of ignore().
Immediately render first 6 contacts in each group.
Contacts search WIP.
Fix null references in multilevel_visibility_monitor
Fix unit tests.
Remove stray debugging statement.