Support autoplay for Video Module and background videos#15

Videos inside Popups should honor the autoplay attribute. Samples, that currently do not autoplay:

Custom Video / Video-Background in Divi Section:

<video autoplay><source src="video.mp4" type="video/mp4"></video>

YouTube:

<iframe width="640" height="360"
  src="http://www.youtube.com/embed/M7lc1UVf-VE?autoplay=1"
  frameborder="0"></iframe>

Vimeo:

<iframe width="640" height="360"
  src="https://player.vimeo.com/video/76979871?autoplay=1"
  frameborder="0"></iframe>