Stubs for fetch module
Definition of Request and related enums
Definition of Response and related enums/concepts
Revert the rust-mozjs changes to support threadsafe SpiderMonkey.

These changes were integrated accidentally, and now cause segfaults during
conservative stack scanning.
Add 'set -e' to the Travis OSX script.

This ensures that the script actually fails if the build didn't succeed.
Fix stuff in fetch crate
Merge pull request #2990 from Ms2ger/revert-threadsafe

Revert the rust-mozjs changes to support threadsafe SpiderMonkey. ;r=jdm, Manishearth
Merge pull request #2962 from Manishearth/fetch

Start of fetch module; r=jdm
Merge pull request #2992 from Ms2ger/set-e-osx

Add 'set -e' to the Travis OSX script; r=Manishearth
Return 'BackCompat' for document.compatMode only if in quirksmode
Mark linebreak_simple_a.html as flaky on cpu reftests.

It has failed on three unrelated PRs:

https://s3.amazonaws.com/archive.travis-ci.org/jobs/31574326/log.txt
https://s3.amazonaws.com/archive.travis-ci.org/jobs/31581185/log.txt
https://s3.amazonaws.com/archive.travis-ci.org/jobs/31592052/log.txt
Merge pull request #2997 from Ms2ger/flaky-reftest

Mark linebreak_simple_a.html ass flaky on cpu reftests; r=SimonSapin
Use TaskBuilder to spawn worker threads.
Use TaskBuilder for the main Servo task.
Merge pull request #2996 from hazz/document-compatmode

Return 'BackCompat' for document.compatMode only if in quirksmode; r=Ms2ger
remove unnecessary clone usage
Un-blacklist the layout crate from rustdoc. See #2924.

Whatever rustdoc bug we used to hit was solved by the Rust upgrade.
(The style crate still causes rustdoc to overflow its stack.)

Also use Markdown tables rather than ASCII diagrams in inlines.rs.
Not only does this look nicer, this works around rustdoc trying
(and failing) to parse them as Rust code.
Move documentation table stylining to a shared location.
Blacklisted docs don’t need any dependency, since we don’t actually generate them.
Merge pull request #3001 from jxs/master

remove unnecessary clone usage