Don't show the enable authy view if this is already enabled
Adding the ability to remember a device and skip entering a token on login.
Merge remote-tracking branch 'pyronicide/remember-device' into integration
Move remember_device method to Helpers.

Also, fixed a couple of typos and updated the demo.
Refactoring the code.

1. `check_request_and_redirect_to_verify_token` is only called when the
   user is signing in.
2. optimize `check_request_and_redirect_to_verify_token`
3. refactor `require_token?` method to return true by default.
Add a flash message when the entered token is invalid.
Fix translation missing
Bump version and regenerate gemspec.