Pass scripts as ~str to support non-ASCII string literals etc.

Of course scripts on the Web are not always encoded as UTF-8 and we will have
to deal with that at some point.
Convert between JS and Rust strings in a way that handles Unicode

This doesn't handle invalid UTF-16 and may not be efficient.  It's just a small
change to make things better until we decide what we're doing about strings in
the long run.

Fixes #1068.
Test non-ASCII tag names
Remove unused aTriedToWrap argument.
auto merge of #1078 : Ms2ger/servo/triedToWrap, r=jdm
Make Node.owner_doc private.
auto merge of #1066 : Ms2ger/servo/priv-owner-doc, r=jdm

When `Document` is a `Node`, we can only set its `owner_doc` after creating the `AbstractDocument`, and thus the `Document`, and thus the `Node`; i.e., when creating the `Node`, the `AbstractDocument` can't exist yet. That means that we'll need to turn `owner_doc` back into an `Option`. We don't want to expose that to everyone, though, so this adds encapsulation so we'll be able to just `unwrap` in the `owner_doc()` function rather than at all call sites.
Remove an unnecessary cast::transmute call.
auto merge of #1080 : Ms2ger/servo/get_jsobject-cast, r=jdm
Check for allocation failure in domstring_to_jsval
Update comment with spec link
Fix broken testcase in rust-mozjs
auto merge of #1077 : kmcallister/servo/jsstr, r=jdm

This doesn't resolve the big questions of how Servo will represent strings; it's just about doing the conversion correctly for our existing types.
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