Implement HTMLDListElement binding.
Fix doubling noncontent_height in float flow
auto merge of #739 : ILyoan/servo/acid1_margin, r=metajack

In `assign_height_inorder_float()`, `base.position.size.height` already counted padding and border, so adding `noncontent_height` to `height` would result in doubling counted padding and border.

By this patch acid1 would be displayed more accurately.

Not sure but maybe width has the same problem, I'll investigate it.
Add NodeStatus enum, infrastructure for compositor-side invalidation
auto merge of #743 : eschweic/servo/dlbi, r=kmcallister

A few changes to the compositor to support invalidate_rect requests from layout.

r? @kmcallister
Pass --cfg debug to rustc
auto merge of #744 : kmcallister/servo/debug, r=metajack
add rect to FrameTree
add comment re: clipping rect
placeholders for FrameRectMsg from Layout to Constellation
add rect to FrameTree
added CompositorLayer::from_frame_tree
reorganized constellation.
compositor routes dom events via constellation.
constellation handles iframe sizing and resizing.
refactor iframe element fields to support sending size to the constellation
support in layout to send iframe sizes
removed old TODO
add iframe support
some more minor refactoring in constellation
Better layer resize methods
move navigation_type from Pipeline to FrameChange