Remove rust-glut
Update submodules for new Rust version
Linter changes
Trait changes, and eliminate 'copy'
Library changes
Convert our iterators to external iterators

Except util/tree.rs (see next commit).
Reorganize tree ref / node traits

rustc is no longer happy with

    impl<NR:TreeNodeRef<N>,N:TreeNode<NR>> TreeUtils for NR
For loops and misc changes
Stub out some things that need changes for newrt

brson and I will work on these next.
Remove HTTP support (!)

We'll need a new HTTP client lib written against newrt.
Update Rust version again

This gets us the new runtime.
Un-stub timer code
Put the compositor on the main thread in the newrt way
Remove start() when building the test harness

Otherwise it will take over before the harness code has a chance to run.
Force a rebuild of rustc
Fix macos interators, warnings, and updating submodules.
Revert to using -o for tests
auto merge of #735 : kmcallister/servo/rust-upgrade, r=kmcallister,metajack

Was #734.