rustc: Dispose of LLVM passes in test cases
libsyntax: Remove `drop` as a keyword.
Fix update snapshot script for rename
Ignore rustpkg tests
core -> extra for mac
xfail box-related debug-info tests r=snapshot
ignore inherited environment test under valgrind r=snapshot
_Actually_ xfail debuginfo tests
Remove all #[cfg(stage0)]-protected code

New snapshot means this can all go. Also removes places that have
comments that say they are workarounds for stage0 errors.
libstd: cleanup warnings
libsyntax: cleanup warnings
libextra: cleanup warnings
librust: cleanup warnings (except 1)
Update snapshots.txt
Fix let bindings in trans/borrowck
rebase wip
wip

remaining failures:

failures:
    [run-pass] /home/nmatsakis/versioned/rust-2/src/test/run-pass/issue-2642.rs
    [run-pass] /home/nmatsakis/versioned/rust-2/src/test/run-pass/match-pattern-drop.rs
    [run-pass] /home/nmatsakis/versioned/rust-2/src/test/run-pass/placement-new-arena.rs
    [run-pass] /home/nmatsakis/versioned/rust-2/src/test/run-pass/static-method-test.rs
Cleanup arguments in _match::store_arg, remove dup code from base
remove assert that does not hold until we make lets more direct
Move all local variable initialization into _match::store_local()
to accommodate things like "let x: uint = return"