Close #84

Actually <img> elements in <noscript> are not prefetched anymore.

Probably because html5ever already parses the <noscript> content as raw
text data if `scripting_enabled` is activated.

See
https://github.com/servo/html5ever/blob/servo/src/tree_builder/rules.rs#
L126

Also, added a test to the images cache.
embedding: begin cef string_map api

cef_string_map_alloc()
embedding: cef_string_map_size()
embedding: cef_string_map_append()
embedding: cef_string_map_find()
embedding: cef_string_map_key()
embedding: cef_string_map_value()
embedding: cef_string_map_clear()
embedding: cef_string_map_free()
embedding: rename string_list internal function to string_list instead of string_map
embedding: cef_string_utf8_cmp()
Enable the cors/ wpt subset

Fixes #3781
auto merge of #3958 : zwarich/servo/remove-libgreen, r=Ms2ger
Change /cors/remote-origin.htm.ini to CRASH
auto merge of #3952 : andrewguertin/servo/wpt-cors, r=Manishearth

Fixes #3781 

I had to make a small fix to wptrunner's wptupdate, but otherwise the instructions at https://github.com/servo/servo/blob/master/tests/wpt/README.md#updating-test-expectations were good and this was very straightforward.
Clip display list based on frame viewport

Instead of creating a display list for the entire page, only create one
for an area that expands around the viewport. On my machine this makes
incremental layout of http://timecube.com 50% faster.
auto merge of #3934 : guillaumebort/servo/fix/84, r=jdm

Actually `<img>` elements in `<noscript>` are not prefetched anymore.

Probably because html5ever already parses the `<noscript>` content as raw
text data if `scripting_enabled` is activated.

See https://github.com/servo/html5ever/blob/servo/src/tree_builder/rules.rs#L126

Also, added a test to the images cache.
Rename LoadIframeUrlMsg to CreateIFrameAndLoadUrlMsg

This better reflects what the message does.
Small fix to variable name

This is a more accurate name for the script pipeline.
Add some factory methods for frame tree types