layout: Implement `word-spacing` per CSS 2.1 § 16.4.

This assumes that there are no ligatures that span across multiple
words. Since we have a per-word shape cache, this is a safe assumption
as of now. I have left comments to ensure that, if and when this is
revisted, we make sure to handle it properly.
Factor out part of the traversal routine in HTMLCollection.

I would move the filter() call into the traverse function as well, but the
callback can't outlive its stack frame.
Skip the root node in live HTMLCollections.

The root node is never included in the collection, and omitting it here
simplifies and speeds up the filter implementations.
auto merge of #4363 : Ms2ger/servo/collectionfilter, r=Manishearth
auto merge of #4360 : pcwalton/servo/word-spacing, r=mbrubeck

This assumes that there are no ligatures that span across multiple
words. Since we have a per-word shape cache, this is a safe assumption
as of now. I have left comments to ensure that, if and when this is
revisted, we make sure to handle it properly.

r? @mbrubeck
Make DOMParser::ParseFromString actually parse the string
auto merge of #4297 : ChrisParis/servo/parse, r=Ms2ger

Addresses https://github.com/servo/servo/issues/3756. I've tested this code with a new test that I've submitted to https://github.com/w3c/web-platform-tests.
Run the DOM parsing tests.
layout: Implement `overflow-wrap`/`word-wrap` per CSS-TEXT § 6.2.

This property is used by approximately 55% of page loads.

To implement the line breaking behavior, the "breaking strategy" has
been cleaned up and abstracted. This should allow us to easily support
other similar properties in the future, such as `text-overflow` and
`word-break`.
auto merge of #4361 : pcwalton/servo/overflow-wrap, r=glennw

This property is used by approximately 55% of page loads.

To implement the line breaking behavior, the "breaking strategy" has
been cleaned up and abstracted. This should allow us to easily support
other similar properties in the future, such as `text-overflow` and
`word-break`.

r? @glennw
auto merge of #4365 : Ms2ger/servo/test-domparsing, r=jdm
Run the File API tests.
auto merge of #4370 : Ms2ger/servo/test-fileapi, r=jdm
layout: Make line breaking able to restart from any position.

This commit removes the "merge-fragments" pass from inline reflow,
instead merging "on the fly". This ended up being simpler, as well as
more fine grained. Additionally, this patch makes the line breaker no
longer clone every fragment (!)

This functionality will be used in the implementation of
`text-overflow`.
Make ErrorEvent::new take cancelable and bubbling enums
auto merge of #4372 : thiagopnts/servo/errorevent, r=Ms2ger

Fixes #4174.
Correctly set the BlobType for File objects.
Add handle_key stub to gonk port
Update azure to fix gonk build
auto merge of #4373 : Ms2ger/servo/blob-type, r=Manishearth