Make sure our naming is vertical-writing-direction clean

[pcwalton]

For vertical writing direction, block layout goes left-to-right and inline goes top-to-bottom. We should not bake in assumptions about top-to-bottom and left-to-right/right-to-left into our naming.

[SimonSapin]

As I wrote on the dev-servo mailing list:

Even if the actual feature is not a priority, it might be easier to rewrite the layout code to use logical keywords (eg. measure/extent instead of width/height) while we don’t have much layout code.

http://dev.w3.org/csswg/css-writing-modes/
http://dev.w3.org/csswg/css-writing-modes/#abstract-box

[jdm]

@SimonSapin This is fixed after your changes, yes?

[SimonSapin]

Yes, there is still related work to do, but the naming should be good now.