CSS: rexport types and variants for computed values.
Add parsing a stylesheet form an iterator, a style attr form a string.
Add supported border styles to the CSS parser.
Provide a useful error message when we fail to create the GLFW window
Print GLFW errors
Enable DOMParser test case

Now that #1071 is fixed.
Remove special-casing of URLs ending in ".js"

This was a very old (May 2012) testing feature which used
std::io::read_whole_file rather than our normal resource-loader mechanism.

We can implement javascript: URLs later.
Factor out a convenience function load_whole_resource

Also remove an unnecessary spawn in js_script_listener, and remember the final
script URL after redirects.
Add a spawn_with! macro and clean up some spawns
auto merge of #1082 : kmcallister/servo/misc, r=jdm
Remove DerivedWrapper::wrap_shared, as it's unused.
Remove unused DerivedWrapper implementations.
auto merge of #1085 : Ms2ger/servo/wrap_shared, r=jdm
Add the test about Element attributes.
Enable to update Element's attributes.
Merge BindingObject and Reflectable.
auto merge of #1086 : Ms2ger/servo/GetParentObject, r=jdm
Remove @pointers from Stylesheet to make it Sendable

… at the cost some extra copying.

This fixes #1081.
CSS: Add a ComputedValues::resolve_color() helper, for currentColor.
CSS: Make sure computed values implement Eq and Clone.