Add CSS Shapes feature
Create ambient-light.json

Added the Ambient Light API
add same position:sticky polyfill recommended by html5please

See https://github.com/h5bp/html5please/blob/master/posts/css-sticky.md
Update mpeg4.json

Added note about incompatibilities with Firefox on OS X
Merge pull request #543 from AurelioDeRosa/patch-1

Create ambient-light.json
Merge pull request #544 from cvrebert/patch-1

add same position:sticky polyfill recommended by html5please
Merge pull request #545 from dr0id-in/patch-1

Update mpeg4.json
data update
Update iframe-sandbox.json

FireFox was updated in version 28 to allow popups in sandboxed iFrames.

https://bugzilla.mozilla.org/show_bug.cgi?id=766282
doc Firefox input placeholder style compat issue

References:
https://developer.mozilla.org/en-US/docs/Web/CSS/::-moz-placeholder
https://bugzilla.mozilla.org/show_bug.cgi?id=556145
Merge pull request #547 from davidjbradshaw/patch-1

Update iframe-sandbox.json
Merge pull request #549 from cvrebert/patch-1

document Firefox input placeholder style compat issue
data update
Merge pull request #527 from fliptheweb/css-shapes

Add CSS Shapes feature
data update