Updates to DPC to improve page load times

[emmattiussi]

Changes made:

• Moved player.js script out of head an onto about.md
• Added async attribute to player.js script tag on about.md
• Deleted jQueryUI - replaced animate method with CSS transitions.
• Carousel controls weren't showing on viewport on some mobile devices - reset positions to ensure they were visible at all times.

To Review

• Quality control on new CSS transitions:
  • jQueryUI animate method animates non-numeric CSS properties.
  • In this case, it was being used to animate the background-color of the header on the mobile site menu: when the mobile menu was opened, the header (IF logo, site name) would be animated to opacity: 1 and background-color: white (vice versa when menu closed).
  • May be some slight changes in framerates on the animation in CSS transitions. Would be great to see what you both think.
  • Removing jQueryUI improves page load time by 15-20%, depending on metrics you're looking at.

Thank you!