rewrote register logic and feature;
some modification on sign in feature;

Signed-off-by: TomWu <phperwuhan@gmail.com>
fixed bug:the 'invitation' case registration method can cause registration failed,so make it to basic method.
fixed bug:in sign_in 5 parameters case and 'approval' case registration method case,the new user can not be actived directly and login directly.
prepare In App Registration backend settings.

Signed-off-by: TomWu <phperwuhan@gmail.com>
add four settings for In App Registration feature on framework level.
calculate the flags for In App Registration.

Signed-off-by: TomWu <phperwuhan@gmail.com>
implemented In App Registration.

Signed-off-by: TomWu <phperwuhan@gmail.com>