title: hide/show fab with scale animation
body: <p>I'm using custom floatingactionmenu. I need to implement scale animation on show/hide menu button like here
  <a href="https://material-design.storage.googleapis.com/publish/material_v_4/material_ext_publish/0B6Okdz75tqQsZU1kZWhRYWZpUDg/components-buttons-fab-behavior_01_xhdpi_012.mp4" rel="noreferrer">floating action button behaviour</a></p>
  
  <p>Is there any way to do this ?</p>