- Some basic validation of user email addresses

- AJAX auto-updating of "N problems solved and counting"

Fix 404 page

- Show 404 page for /user/dsfsdfhsvdvd

- Nicer 404 pages
- Improve emails on accepted answer-submissions

Fix links on Top 100 page

- Improve data-tables behavior on All Users page

- Fix: incorrect reset-password URL was being mailed to users

Stop using such an atrociously old version of hiccup.

It seems to have been conflicting with one of our other dependencies.

- Add API for getting data about problems

- Server-side paging/filtering of All Users page
- Improve Account Settings page and Gravatar support

Use different default-gravatar for profile pages

Use default gravatar images

Gravatars for users