[css-compositing]new Editor's draft posted

All,

a new version of the compositing and blending spec was posted here:

https://dvcs.w3.org/hg/FXTF/rawfile/default/compositing/index.html


I removed the following features that were not going to make it in level 1:

- compositing on CSS element
- compositing on backgrounds in CSS
- shorthand that combines blending and compositing
- knock-out

They will be moved to the next version of the specification.

The biggest open issue in the spec is defining how 'grouping' is defined so
we can get inter-operable behavior across browser engines. [1]
We're currently working on a test matrix that explores browser differences
in this area.

Please review if you have time and let me know if you have any concerns.
I would like to publish this as a new Working Draft.

1:
https://dvcs.w3.org/hg/FXTF/rawfile/default/compositing/index.html#csscompositingrules_CSS