Add debug info for boxes
Add debug info for vectors
Add debug info for bare_fn type
Prevent debug info generation of zero-span nodes

If a node has a (0, 0) span, it was not in the source, so debug symbols should not be generated for it.
Add debug info test for boxes
Add debug info test for vectors
core: add vec::bsearch.
core: replace unicode match exprs with bsearch in const arrays, minor perf win.
xfail box and vec debug info tests
librustc: Remove `fail_unless!`
librustc: Implement fast-ffi and use it in various places
rustllvm: Fix RustWrapper.cpp
librustc: Switch the `@`s in types with `~`
librustc: Take primitive types out of the type hash table.
librustc: Remove def_ids from types.
librustc: Optimize metadata::decoder::item_name.
libstd: Micro-optimize vuint_at
rt: Fix scalability problem with big stacks on 32 bit
librustc: Improve inlining behavior.
llvm: Fixes for RustWrapper.