MessageTree:
  - Add expand/collapse-all buttons and menu items
  - Add icons to some buttons
  - Enable/disable expand/collapse-thread/all-buttons/menus as appropriate
  - Better layout of buttons
  - Spinner tweaks
  - cleanups, finals
- Set icon on MessageView reply button

1.102b-10
refactor date/time utils to their own class
- Add support for 1- and 2-arg gettexts
- Add better quote message, tag it
- Add attachment count to ThreadReferenceNode
- Show attachment icon in MessageTree for those with attachments
- Clean up tooltips for links