Small styling tweaks to note buttons etc
More tedious refactoring of inline note display.

 - attempted to simplify markup
 - moved visibility toggle for other people's notes to the header
 - improved styling and icons for inline notes
 - added custom JS to show/hide note bubbles

The description notes still need work.
More tedious refactoring of inline note display.

 - attempted to simplify markup
 - moved visibility toggle for other people's notes to the header
 - improved styling and icons for inline notes
 - added custom JS to show/hide note bubbles

The description notes still need work.
When an annotation is edited, check if its visibility should have
changed and update if necessary.