Reenable the second wpt chunk.
layout: Remove `layout/extra.rs`.

Also, rename a few methods in layout that arguably had confusing names.
Dump initial prototype of devtools server into the build. Expect lies if you try to use it for anything real.
Enable executing JS snippets in the context of the main Servo window and viewing the responses from the Firefox remote console.
Split devtools implementation into sensible modules.
Avoid selecting on the devtools port if no devtools server exists.
Implement wire protocol support for DOM inspector.
Enable real DOM inspector support.
Retrieve some basic layout properties for nodes to make the box model somewhat useful.
Implement TreeWalker
Fix line splitting in `white-space: pre` flows

The newline position from one line was getting used repeatedly, causing extra
"phantom" newlines in the following lines.  Fixes #3413.
Remove uses of &mut JSRef

Since everything with JSRef happens with interior mutability, it doesn't
make any sense to use an &mut JSRef.
Merge pull request #3414 from mbrubeck/pre-line-break

Fix line splitting in `white-space: pre` flows. r=gw
Fix padding on tables. This fixes the TOC on wikipedia pages.

Ref: #2554
Merge pull request #3416 from zwarich/remove-jsref-mut

Remove uses of &mut JSRef
Merge pull request #3421 from glennw/table-padding

Fix padding on tables. This fixes the TOC on wikipedia pages.
Fix img with display: block. Fixes text/image overflow on wikipedia.

Ref: #2554
Merge pull request #3419 from glennw/img-block

Fix img with display: block. Fixes text/image overflow on wikipedia.
Fix dimensionality of Au

Previously, we implemented:

Au * Au -> Au
Au / Au -> Au
Au % Au -> Au

... which are inconsistent. It should be:

Au * Au -> SquaredAu
Au / Au -> i32
Au % Au -> i32

or:

Au * i32 -> Au
Au / i32 -> Au
Au % i32 -> Au

I picked the latter.

Also, the multiplicative identity does not make sense
when multiplication take two different types.
Remove min/max functions from util::geometry. Use std::cmp instead.