upgrade backbone: 0.9.2 -> 0.9.10
upgrade underscore: 1.3.3 -> 1.4.3
update url in registration documentation
refactor register view; some other refactorings
new registration form

email and notify checkboxes are not saved anywhere yet
backend: save settings on /register
backend: throw exceptions on /register errors
backend: /register settings parameter is json-encoded
save settings on registration; error-handling
s/User Settings/Player Settings/
user settings available from current user dropdown menu
Merge branch 'settings-on-register'

Continuing http://play-perl.org/quest/5116a6082dfd480c28000016.