serious mode engaged: start of embedding crate using FFI

current status

=============

[ ] Successfully crashing CEF

[X] Successfully not crashing CEF
add readme for using embedding crate
auto merge of #2408 : zmike/servo/embedding-invasion, r=jdm

This adds further support for crashing CEF and world domination.

@larsbergstrom
Update rust-layers submodule

This should fix rendering issues on NVidia and perhaps Catalyst drivers.

Fixes #2315.
auto merge of #2488 : mrobinson/servo/update-rust-layers-nvidia, r=larsbergstrom

This should fix rendering issues on NVidia and perhaps Catalyst drivers.
Make RenderChan a newtype struct.

Also, derive Clone rather than implementing it manually.
Clean up AttributeHandlers::get_attribute() for JSRef.
auto merge of #2489 : zwarich/servo/render-chan-newtype, r=jdm

Also, derive Clone rather than implementing it manually.
auto merge of #2491 : saneyuki/servo/attr, r=jdm
Move some of the box splitting logic into inline.rs
Use a SplitInfo struct instead of a tuple to make the code more self-documenting
Move box splitting by new-line to inline.rs
Improve function naming
Update to owned::Box
Use StrBuf more efficiently in htmlserializer.
Rewrite escape() in htmlserializer to push onto a StrBuf.
auto merge of #2484 : Ms2ger/servo/htmlserializer-strbuf, r=jdm
Add stubs for inline event handler manipulation.
Implement window forwarding for body event handlers.
Compile JS strings when setting inline event handlers via element attributes.