std::trie: add benchmarks for insert.
std::trie: optimise insert slightly.

This reduces the number of moves/memcpy's we do, which makes insert
faster, especially in cases of keys with long equal prefixes (the
_low_bits tests):

Before:

    bench_insert_large                ... bench:    553966 ns/iter (+/- 64050)
    bench_insert_large_low_bits       ... bench:   1048151 ns/iter (+/- 92484)
    bench_insert_small                ... bench:    168840 ns/iter (+/- 22410)
    bench_insert_small_low_bits       ... bench:    185069 ns/iter (+/- 38332)

After:

    bench_insert_large                ... bench:    422132 ns/iter (+/- 35112)
    bench_insert_large_low_bits       ... bench:    339083 ns/iter (+/- 34421)
    bench_insert_small                ... bench:    134539 ns/iter (+/- 15254)
    bench_insert_small_low_bits       ... bench:     88775 ns/iter (+/- 5746)
Removed redundant code, improve performance

closes #10535
auto merge of #11546 : huonw/rust/trie-insert, r=alexcrichton

This reduces the number of moves/memcpy's we do, which makes insert
faster, especially in cases of keys with long equal prefixes (the
\_low_bits tests):

Before:

    bench_insert_large                ... bench:    553966 ns/iter (+/- 64050)
    bench_insert_large_low_bits       ... bench:   1048151 ns/iter (+/- 92484)
    bench_insert_small                ... bench:    168840 ns/iter (+/- 22410)
    bench_insert_small_low_bits       ... bench:    185069 ns/iter (+/- 38332)

After:

    bench_insert_large                ... bench:    422132 ns/iter (+/- 35112)
    bench_insert_large_low_bits       ... bench:    339083 ns/iter (+/- 34421)
    bench_insert_small                ... bench:    134539 ns/iter (+/- 15254)
    bench_insert_small_low_bits       ... bench:     88775 ns/iter (+/- 5746)

Notably: no unsafe code.
remove reference counting headers from ~

Unique pointers and vectors currently contain a reference counting
header when containing a managed pointer.

This `{ ref_count, type_desc, prev, next }` header is not necessary and
not a sensible foundation for tracing. It adds needless complexity to
library code and is responsible for breakage in places where the branch
has been left out.

The `borrow_offset` field can now be removed from `TyDesc` along with
the associated handling in the compiler.

Closes #9510
Closes #11533
remove `borrow_offset` as ~ is now free of headers
add implementation of `Repr` for `~[T]`
Mark LineIterator as public so its docs get generated.
extra: Ignore time tests on android correctly
auto merge of #11547 : b1nd/rust/rust-doc, r=alexcrichton

closes #10535
auto merge of #11535 : thestinger/rust/header, r=alexcrichton

Unique pointers and vectors currently contain a reference counting
header when containing a managed pointer.

This `{ ref_count, type_desc, prev, next }` header is not necessary and
not a sensible foundation for tracing. It adds needless complexity to
library code and is responsible for breakage in places where the branch
 has been left out.

The `borrow_offset` field can now be removed from `TyDesc` along with
the associated handling in the compiler.

Closes #9510
Closes #11533
libstd: Added more #[inline] annotations and replaced uses of `libc::abort` with the intrinsic.
auto merge of #11557 : brson/rust/anotherandroidfix, r=thestinger
Fix formatting in rust-guide document.
auto merge of #11556 : am0d/rust/docs, r=huonw
auto merge of #11561 : eddyb/rust/moar-inlines, r=pcwalton
auto merge of #11564 : am0d/rust/dox, r=huonw

Needs a line break here for readability.
Add a configure to disable libstd version injection

We'll use this when building snapshots so we can upgrade freely, but all
compilers will inject a version by default.
auto merge of #11523 : alexcrichton/rust/stage3, r=brson

This should go back to the old behavior while preserving the snapshot ease.
Shuffle around ownership in concurrent queues

Beforehand, using a concurrent queue always mandated that the "shared state" be
stored internally to the queues in order to provide a safe interface. This isn't
quite as flexible as one would want in some circumstances, so instead this
commit moves the queues to not containing the shared state.

The queues no longer have a "default useful safe" interface, but rather a
"default safe" interface (minus the useful part). The queues have to be shared
manually through an Arc or some other means. This allows them to be a little
more flexible at the cost of a usability hindrance.

I plan on using this new flexibility to upgrade a channel to a shared channel
seamlessly.