Allow resource load failures to send an error string which is reporting during task failure.
fix android build
auto merge of #2367 : aydinkim/servo/PR, r=larsbergstrom

With Rust syntax changing..
Rename an unused parameter that triggers a warning.
auto merge of #2368 : zwarich/servo/net-unused-param, r=metajack
Fix for parallel data race in layout code. Fixes #2308.
Add ProgressEvent interface
auto merge of #2355 : glennw/servo/http-fail-errors, r=jdm

...during task failure.
auto merge of #2361 : Manishearth/servo/progressevent, r=jdm

Adds the ProgressEvent webidl and implementation according to the XHR spec.

Blocks #2282
auto merge of #2369 : glennw/servo/issue-2308, r=metajack

There might be a "cleaner" rust way to separate the scope and invoke the drop() call?