Update rust-http-client to make tests pass.
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