remove bindings codegen h/cpp files from .gitignore

These files don't exist in the tree, and the codegen doesn't create
them, so we shouldn't have them sitting around in .gitignore.
Fixed #4127: Added a fast path to border-radius.

This will avoid drawing Arcs if there's no border-radius property set.
code review
Have 'mach doc' copy Rust documentation.
Replace `mach serve-docs` by `mach browse-doc`, fix #3913
Fixed #4170 - Incremental reflow wasn't being aggressive enough when nodes get reparented.

When inserting a node that was already dirtied, the dirtying logic
would short circuit: "This node is already dirty? Great! Then its
parents must be HAS_DIRTY_DESCENDANTS, too! Let's skip that step."

This isn't appropriate when nodes move around the tree. In that case,
the node may be marked HAS_CHANGED, but ancestors may not yet have
the HAS_DIRTY_DESCENDANTS flag set.

This patch adds a `content_and_heritage_changed` hook in the document,
to deal with these cases appropriately.
auto merge of #4142 : SimonSapin/servo/refactor-doc, r=Manishearth
Implement Window.sessionStorage: Storage Task, Storage Methods (excluding Storage event, QuotaExceededError)
Remove libgreen support.
Make 'mach doc' not fail when components/servo/target doesn’t exist.
auto merge of #4157 : nkdalmia/servo/master, r=jdm

Changes
* Implemented Storage Task
* Used Storage Task in methods of storage.rs
* Updated webstorage test expectations

Pending Changes:
* Handle Storage Event
* Throw QuotaExceededError in case of failure for method setItem
* localStorage as alias of sessionStorage
Fix 'mach browse-doc' to use the right target directory.
auto merge of #4187 : cgaebel/servo/issue-4127, r=SimonSapin

This will avoid drawing Arcs if there's no border-radius property set.

Fixes #4127
Update web-platform-tests.
auto merge of #4202 : zwarich/servo/remove-libgreen, r=larsbergstrom
auto merge of #4205 : servo/servo/wpt_20141202, r=jdm
Update skia submodule to get android build fix.
auto merge of #4203 : SimonSapin/servo/refactor-doc, r=Manishearth
Support for Separated Read Write
auto merge of #4210 : glennw/servo/skia-android-update, r=metajack