Update to Rust 0.6 syntax.
Update build flags for latest Clang.
Merge pull request #10 from metajack/rust-0.6-syntax

Rust 0.6 syntax
Add license
Remove unused imports.
Merge pull request #11 from metajack/unused-imports

Remove unused imports.
Change LinearMap to HashMap.
Merge pull request #12 from metajack/new-hashmap

Change LinearMap to HashMap.
Add license headers
Fix makefile for GCC 4.2
Unconditionally append to CFLAGS.
Make JSFUN_CONSTRUCTOR share the corresponding value from mozjs.
Add tracing enum.
Make GC work.
Work around bizarre compilation error with debug builds of mozjs.