Add a new Digest.result_bytes convenience function.
std::result: Remove function `map_opt`

This function has never had any users in the tree
Disable zlib/libffi when configuring LLVM

This should help bring fewer dependencies in to the snapshots.

Closes #9397
tutorial.md : correct formula in fn area()

change formula (other solution could be using abs()).
add `noreturn` attribute to functions returning !

Closes #9317
std: Replace CloneableTuple with Tuple, which takes self by-val.

The old behaviour of `foo.n0()` is replaced by `foo.n0_ref().clone()`.
#7752: use fcnptr for glob errfunc.
auto merge of #9491 : thestinger/rust/noreturn, r=huonw

Closes #9317
auto merge of #9428 : alexcrichton/rust/llvm-zlib-and-libffi, r=pnkfelix

This should help bring fewer dependencies in to the snapshots.

Closes #9397
std: Add an is_parent_of method to Path
rustpkg: Search for packages correctly when using the rust_path_hack

Previously, any package would match any other package ID when searching
using the rust_path_hack, so long as the directory had one or more crate
files in it. Now, rustpkg checks that the parent directory matches the
package ID.

Closes #9273
auto merge of #9493 : huonw/rust/move-tuples, r=thestinger

The old behaviour of `foo.n0()` is replaced by `foo.n0_ref().clone()`.
0.8 will be in September
Don't die in try_unsafe_borrow if tls isn't ready

If there's no TLS key just yet, then there's nothing to unsafely borrow, so
continue returning None. This prevents causing the runtime to abort itself when
logging before the runtime is fully initialized.

Closes #9487
auto merge of #9498 : catamorphism/rust/rust-path-hack-fix, r=cmr,metajack

r? @metajack
Rename from_utf8 to from_bytes again
auto merge of #9345 : Dretch/rust/digest-result-bytes, r=cmr

I would find this function useful.
rustdoc: Add sundown to src/rt/

This also starts compiling it in the same manner as linenoise, it's just bundled
with librustrt directly, and we export just a few symbols out of it.
rustdoc: Use sundown for markdown highlighting

This takes rendering times of documentation down from 30s to 0.5s. Kinda sad
that none of the parallelism is needed, but oh well!

Closes #7380
cc #3546
rustdoc: Change all code-blocks with a script

    find src -name '*.rs' | xargs sed -i '' 's/~~~.*{\.rust}/```rust/g'
    find src -name '*.rs' | xargs sed -i '' 's/ ~~~$/ ```/g'
    find src -name '*.rs' | xargs sed -i '' 's/^~~~$/ ```/g'