User can edit or deactivate their account
Refactor session handling for disabled accounts

Don't sign in the user until after their account_enabled status has been
verified.
Add confirmation dialog on delete
Add before filter for sessions, add flash partial
Refactor disable user account and session handling for disabled users
Merge branch 'lea-user-can-disable-account'

* lea-user-can-disable-account:
  Refactor disable user account and session handling for disabled users
  Add before filter for sessions, add flash partial
  Add confirmation dialog on delete
  Refactor session handling for disabled accounts
  User can edit or deactivate their account