Expand chained timing functions

[steveblock]

No description provided.

[birtles]

Pushed a changeset based on this:
https://dvcs.w3.org/hg/FXTF/rev/9ea455a47bf4

We agreed to only allow specifying the x positions of a chained timing function for now so that's all I've added for now. Likewise I haven't added smoothing.

[steveblock]

Looks good Brian! I really like 'distribute' and 'align'.

My initial reaction was that it's a shame to require authors to include '0'
at the start of 'easingTimes: it seems unnecessary and a little ugly that
the lengths of 'easing' and 'easingTimes' don't match. But I guess that if
we plan to relax the restrictions on timing functions to operate outside
the range [0,1], we'll want to relax the restrictions on 'easingTimes'
similarly, and we'll then need both limits to be explicitly specified.

Steve

[birtles]

Yeah, I wondered about that. Originally I specced it so you wouldn't fill in 0 or 1 but it seemed a bit odd to me to just say easingTimes: 0.75. I hadn't really thought about forwards compatibility but that's a good point.

[steveblock]

I've updated this branch to reflect Brian's updates to the spec to add timing functions chains. These commits add the ability to specify output times in the timing function position list, and add smoothing. They're not for immediate inclusion in the spec but are uploaded to document the latest proposal on these topics.