Made email address mandatory.  User must enter code emailed to them to be able to comment or post.
Minor clean up.
Changing email address reprompts email verification.
Force a user who has no email to provide one to change their password.
Merge branch 'passwordmandate' of https://github.com/PotatoDumplings/lesswrong into require-email
Simplify random email verification code generator
Update register message now that email is required
Merge branch 'require-email'