(ARCHIVE tag): Document C-TAB for forcing cycling of
archived trees.
(Checkboxes): Section moved to chapter 5, and extended.
(The date/time prompt): New section.
(Link abbreviations): New section.
(Presentation and sorting): New section.
(Custom agenda views): Section completely rewritten.
(Summary): Compare with Planner.
(Feedback): More info about creating backtraces.
(Plain lists): Modified example.
(Breaking down tasks): New section.
(Custom time format): New section.
(Time stamps): Document inactive timestamps.
(Setting tags): More details about fast tag selection.
(Block agenda): New section.
(Custom agenda views): Section rewritten.
(Block agenda): New section.