Add note related to the vibrancy and constraints
Add note related to the vibrancy and constraints

seanwoodward/IBAnimatable,seanwoodward/IBAnimatable,IBAnimatable/IBAnimatable,JakeLin/IBAnimatable,IBAnimatable/IBAnimatable,alexiosdev/IBAnimatable,alexiosdev/IBAnimatable,IBAnimatable/IBAnimatable,JakeLin/IBAnimatable