Fix #1264: support namespaced attribute selectors.
layout: Make "height" relative to the initial containing block for the root.

Fixes Wikipedia.
layout: Change `~Box` to `Box`.

63% improvement in box building on the rainbow page.
auto merge of #1371 : pcwalton/servo/flatten-box, r=larsbergstrom

63% improvement in box building on the rainbow page.

r? @larsbergstrom
make font/platform/gfx/font_context safe
remove @ in LayoutTask.FontContext
makes linux/Arc<FontContextHandle> Rc<FontContextHandle>
auto merge of #1372 : ksh8281/servo/remove_@_in_LayoutTask.FontContext2, r=pcwalton

Remove @ in layout task.font_context & fix linux/FontContextHandle
Arc<FontContextHandle> -> Rc<FontContextHandle>
Merge pull request #1370 from pcwalton/height-containing-block

layout: Make "height" relative to the initial containing block for the root.
Merge pull request #1368 from SimonSapin/master

Fix #1264: support namespaced attribute selectors.
net: Color space convert 32-bit ARGB PNGs as well.
Merge pull request #1379 from pcwalton/png

net: Color space convert 32-bit ARGB PNGs as well.
test: Add missing line in reftest list. rs=sillytestfix
layout: Don't delete non-text boxes from the list of input boxes when
flushing text clumps. Fixes this page:

    http://en.wikipedia.org/wiki/Yellow_River

This is not the most efficient thing to do; a FIXME has been added
noting what is most correct.
auto merge of #1381 : pcwalton/servo/bogus-box-deletion, r=jdm

flushing text clumps. Fixes this page:

    http://en.wikipedia.org/wiki/Yellow_River

This is not the most efficient thing to do; a FIXME has been added
noting what is most correct.

r? @jdm
contenttest: Print stderr
Kill Servo instead of displaying about:failure when running content tests

Fixes #1380.
contenttest: Fail if Servo exits with non-zero status

Remove "let stdout" to make the borrow checker happy.
Don't clear buffers if we have no native graphics context

Fixes ./servo -z for content that calls window.close(), such as content tests.
auto merge of #1382 : kmcallister/servo/headless, r=jdm

r? @jdm