Second steps
Support for creating highlights
Restrict highlihting mode to logged-in users
Change highlighting mode color to yellowish
highlighing mode: tweak CSS for emphasis on selected highlight
Highlight mode: make new highlights private
Highlight mode: click hl to select
Highlight mode: fix sidebar closing behavior
Highlight mode: ask for confirmation on too short highlights
Highlighting mode: restore ability to make highlights inside highlights
Merged latest stylings from @RawKStar77

(Restored feature: when the button is in the "on" stage, let it always be red.)
HL mode: don't call showViewers multiple times. Debug output.
Removed debug output.
Update Annotator to 706391a74a
Updated Annotator to 5fafbdf7 (maintenance branch)
Bugfix: don't swallow parameter required for showing the adder button
Style highlight cards as requested

Also fix a spelling error in CSS
Highlight card: small fix for icon
Don't allow publishing highlights with no text or tags
bugfix