[std::ascii] Add .to_ascii_opt() and .into_ascii_opt() returning Option

… instead of failing.

Make them default methods on the trait, and also make .to_ascii()
a default method while we’re at it.

Conflicts:
	src/libstd/ascii.rs
Conservatively export all trait methods and impls

The comments have more information as to why this is done, but the basic idea is
that finding an exported trait is actually a fairly difficult problem. The true
answer lies in whether a trait is ever referenced from another exported method,
and right now this kind of analysis doesn't exist, so the conservative answer of
"yes" is always returned to answer whether a trait is exported.

Closes #11224
Closes #11225
Mark provided methods in dead-code pass
Update RELEASES.txt for 0.9
Don't leave lingering files in doc tests

Closes #11234
Add byteswap intrinsics for converting from big/little to host endian

These are similar to the ntoh[s|l] functions in C and have the style of
from_[be|le][16|32|64].
libnative: Use [from|to]_be16 instead of bswap16
libextra: Use from_be32 instead of bswap32 in vuint_at()

Also use the fast version of vuint_at() on all architectures since it now
works on both big and little endian architectures.
Remove `extern mod foo (name="bar")` syntax, closes #9543
Recognize LLVM 3.4 when building on opensuse with --llvm-root specified.
Output columns 1-based. Fixes #10848
Test column offset for #11184
auto merge of #11184 : jhasse/rust/patch-col, r=huonw
Fix comment that's been wrong since ancient times (thanks, @jvns).
Fix typo in lint description.
auto merge of #11245 : alexcrichton/rust/issue-11225, r=pcwalton

Commit messages are a little more descriptive.
auto merge of #11246 : ktt3ja/rust/issue-11224, r=alexcrichton

Close #11224
auto merge of #11248 : brson/rust/0.9relnotes, r=alexcrichton
auto merge of #11265 : c-a/rust/byteswap_from, r=alexcrichton

This patchset adds intrinsics similar to the to_[be|le][16|32|64] intrinsics but for going in the reverse direction, e.g. from big/little endian to host endian. Implementation wise they do exactly the same as the corresponding to_* functions but I think it anyway make sense to have them since using the to_* functions in the reverse direction is not entirely intuitive.

The first patch adds the intrinsics and the two following changes instances of bswap* to use the [to|from]_* intrinsics instead.
auto merge of #11268 : lkuper/rust/trans-comment, r=pcwalton