Document a few undocumented modules in libstd

Hopefull this will make our libstd docs appear a little more "full".
restore auto-detection of text files

We force the usage of LF line endings, but *only* in text files.
Resolves third bullet of #4691, and adds tests for it.  Fix #4691.
fix bug in test.
fixed another test.
util: remove unused `with` function
Uncomment a test. Fixes #4449.
Fix spelling and phrasing in 0.8 release notes
Add a note about improved rustc perf to 0.8 relnotes
Invert --cfg debug to --cfg ndebug

Many people will be very confused that their debug! statements aren't working
when they first use rust only to learn that they should have been building with
`--cfg debug` the entire time. This inverts the meaning of the flag to instead
of enabling debug statements, now it disables debug statements.

This way the default behavior is a bit more reasonable, and requires less
end-user configuration. Furthermore, this turns on debug by default when
building the rustc compiler.
auto merge of #9278 : alexcrichton/rust/ndebug, r=brson

Many people will be very confused that their debug! statements aren't working
when they first use rust only to learn that they should have been building with
`--cfg debug` the entire time. This inverts the meaning of the flag to instead
of enabling debug statements, now it disables debug statements.

This way the default behavior is a bit more reasonable, and requires less
end-user configuration. Furthermore, this turns on debug by default when
building the rustc compiler.
auto merge of #9276 : alexcrichton/rust/dox, r=brson

Hopefull this will make our libstd docs appear a little more "full".
Fix example in std::Option
std: add missing #[inline] annotation to the f64 neg method.

This was, somehow, missed by #8332.
auto merge of #9371 : thestinger/rust/text, r=pnkfelix

We force the usage of LF line endings, but *only* in text files.
auto merge of #9349 : brson/rust/relnotes, r=thestinger
auto merge of #9350 : pnkfelix/rust/fsk-issue-4691-catch-bad-fsu-during-compute-moves, r=nikomatsakis

Resolves third bullet of #4691: if the functional-struct-update (FSU) expression `{ a: b, ..s }` causes `s` to move and `s` has a destructor, then the expression is illegal.

r? @nikomatsakis
drop `extra::par`

This was a dead end experiment, and not a sensible way of implementing
generic data parallelism. This also removes the `graph500-bfs.rs`
benchmark because it relies on `extra::par`.

Closes #5626
Document a few undocumented methos in Vector

Closes #9379
Implement a web backend for rustdoc_ng

This large commit implements and `html` output option for rustdoc_ng. The
executable has been altered to be invoked as "rustdoc_ng html <crate>" and
it will dump everything into the local "doc" directory. JSON can still be
generated by changing 'html' to 'json'.

This also fixes a number of bugs in rustdoc_ng relating to comment stripping,
along with some other various issues that I found along the way.

The `make doc` command has been altered to generate the new documentation into
the `doc/ng/$(CRATE)` directories.