Fix bug with overlay

"poster" attribute was added to the wrong element (div instead of
video).
Merge branch 'master' into play-overlay

Conflicts:
	_posts/2014-12-04-activity-fragment-transitions-in-android-lollipop-part1.md
	_posts/2014-12-15-activity-fragment-content-transitions-in-depth-part2.md
Separate inline css into own class