Update comments about Node::layout_data
Add doc and doc-$(crate) targets to the Makefile using rustdoc.
Escape HTML in the cors.rs documentation.

Rustdoc passes the code straight through, leading to poor generated HTML.
Merge pull request #2923 from Ms2ger/cors-escape

Escape HTML in the cors.rs documentation.
Build docs on Travis and upload them to GitHub Pages.

http://servo.github.io/servo/servo/index.html
Merge pull request #2922 from servo/rustdoc

Build rustdoc docs on Travis and upload them to GitHub Pages.
Fix an unnecessary_parens warning.
Merge pull request #2926 from servo/unnecessary_parens

Fix an unnecessary_parens warning.
Merge pull request #2919 from mbrubeck/layout-comments

Update comments about Node::layout_data
Simplify set_clipping_rect and inline it into its only caller
Merge pull request #2928 from zwarich/set-clipping-cleanup

Simplify set_clipping_rect and inline it into its only caller
Add pointers to the relevant issue for some bugs.
Add documentation for the DOM.
Merge pull request #2931 from Ms2ger/dom-docs

Add documentation for the DOM; r=jdm
Assert that we're handed a DOM global in initialize_global.
Merge pull request #2932 from Ms2ger/fixme-347

Add pointers to the relevant issue for some bugs; r=jdm
Track rerender msgs

If the compositor outputs to a file:
* Track rerender msgs sent from the compositor to the render tasks.
* Before outputting, wait until all rerender msgs are processed by the
  render tasks.

Fixes issue https://github.com/servo/servo/issues/2871.
Merge pull request #2930 from bjwbell/track-rerender-msgs

Track rerender msgs
Implement Location.hash.
Merge pull request #2935 from Ms2ger/location-hash

Implement Location.hash.