====== SMIL ======

Synchronized Multimedia Integration Language

====== 참조 링크 ======

  * https://css-tricks.com/guide-svg-animations-smil/
  * http://codepen.io/noahblon/blog/an-intro-to-svg-animation-with-smil
  * http://www.w3.org/TR/SMIL/
  * https://developer.mozilla.org/en-US/docs/Web/SVG/SVG_animation_with_SMIL