Add customize icon animations. Factor out sync animation function.
Fix bugs found during review.
Small changes to customize.less.
Remove tweepy from requirements/prod.txt

Fix broken jenkins build.
This is not needed since we have it as a submodule.
TODO: address inconsitency in playdoh docs that recommend this.
Fix more review bugs:

- Fast images at smaller screen sizes
- Sync section min-height
- Remove superfluous scale3d in customize.less
- Remove negative margin on mobile nav
- Remove leftover attr in intro-anim.html
Bug 1000492 - [australis] [l10n] RTL fixes needed on australis pages