Adds the following functionalities:
 - forgot password
 - reset password on the next login
 - password expiration.
Fixes sender of forgot password email to be configurable
Fixes expiration of change password token to be configurable.
Fixes password reset email to show expiration in email body.
Fixes syntax error: missing closing parenthesis.
Renames NewPasswordPolicy to UserPasswordPolicy
Fixes to handle plurals of expiration in password reset email.
Fixes password policy to honor a user that is updated when changing password.
Fixes to obfuscate a token for resetting password.
Fixes key name for password expiration configuration.
Cleans up
Fixes admin user tool to be able to disable password change.
Merge pull request #25 from perfectsense/feature/password-reset

Features: forgot password?, Password expiration, Change password on the next log in