Update documentation for from_raw_parts

Fixes #19269.
collections: dramatically speed up Vec::reserve with magic

Somehow llvm is able to optimize this version of Vec::reserve
into dramatically faster than the old version. In micro-benchmarks
this was 2-10 times faster. It also shaved 14 minutes off of
rust's compile times.

Closes #19281.
Add doctests for keys() and values() of the BTreeMap collection.

Update keys() and values() for BTreeMap based on @Gankro's comments.

Assign keys and values to variables before doing assertion.
Allow message specification for should_fail

The test harness will make sure that the panic message contains the
specified string. This is useful to help make `#[should_fail]` tests a
bit less brittle by decreasing the chance that the test isn't
"accidentally" passing due to a panic occurring earlier than expected.
The behavior is in some ways similar to JUnit's `expected` feature:
`@Test(expected=NullPointerException.class)`.

Without the message assertion, this test would pass even though it's not
actually reaching the intended part of the code:
```rust
 #[test]
 #[should_fail(message = "out of bounds")]
fn test_oob_array_access() {
    let idx: uint = from_str("13o").unwrap(); // oops, this will panic
    [1i32, 2, 3][idx];
}
```
Change from message to expected
Mention expected in testing docs
auto merge of #19555 : jbranchaud/rust/add-doctests-for-key-values-of-btreemap, r=Gankro
core: remove the dead function fmt::argumentstr.
core: make the public fmt API completely safe.
test: adjust pretty/issue-4264 for formatting changes.
auto merge of #19506 : eddyb/rust/fmt-polish, r=alexcrichton
auto merge of #19560 : sfackler/rust/should-fail-reason, r=alexcrichton

The test harness will make sure that the panic message contains the
specified string. This is useful to help make `#[should_fail]` tests a
bit less brittle by decreasing the chance that the test isn't
"accidentally" passing due to a panic occurring earlier than expected.
The behavior is in some ways similar to JUnit's `expected` feature:
`@Test(expected=NullPointerException.class)`.

Without the message assertion, this test would pass even though it's not
actually reaching the intended part of the code:
```rust
#[test]
#[should_fail(message = "out of bounds")]
fn test_oob_array_access() {
    let idx: uint = from_str("13o").unwrap(); // oops, this will panic
    [1i32, 2, 3][idx];
}
```
auto merge of #19306 : steveklabnik/rust/gh19269, r=nikomatsakis,brson

Fixes #19269.

/cc @thestinger @mahkoh @mitsuhiko
auto merge of #19574 : erickt/rust/vec-reserve, r=alexcrichton

(I don't understand why this works, and so I don't quite trust this yet. I'm pushing it up to see if anyone else can replicate this performance increase)

Somehow llvm is able to optimize this version of Vec::reserve into dramatically faster than the old version. In micro-benchmarks this was 2-10 times faster. It also reduce my Rust compile time from 41 minutes to 27 minutes.

Closes #19281.
Link regions in `ref` bindings from fn arguments.
auto merge of #19456 : nikomatsakis/rust/reborrow-closure-arg, r=pnkfelix

Otherwise region inference can fail when closure arguments include `ref` bindings. Test case included in the PR.
Revert "Register new snapshots"

This reverts commit 9b443289cf32cbcff16768614340f0c844675340.
auto merge of #19645 : alexcrichton/rust/old-snap, r=brson

The most recent snapshot was produced on OSX 10.8, but this segfaults on OSX
10.7 so we need to roll back one snapshot so we can start bootstrapping on 10.7
systems again.

cc #19643
Auto-merging 50b6d01

Travis: Passed at 2014-12-09T13:28:25Z
https://travis-ci.org/vhbit/rust/builds/43439871