Twitter internal documentation update.
do not return on bookmarked content, else the read activation will not be done.
Fix 2 bugs in folder reading list view.
Avoid double-cached-descriptors update, and updating them at every save.

This could probably fix the long-standing bug where users see 2x or 3x more unread items than they really have (one time at save() + one at activate())
version bump for 0.82.2.
Merge branch 'release/0.82.2' into develop