Document a few undocumented modules in libstd

Hopefull this will make our libstd docs appear a little more "full".
librustc/libstd: No longer pass crate_map to start.
libstd/librustc: Make the crate_map a weak symbol that libstd links against.
tests: Remove crate_map from start.
Clarify that snapshots are automatically retrieved.
Update rustpkg manpage to add init.

I didn't update the manpage when I added the init command. Whoops.
Fix unresolved symbol error for the crate_map in libstd on os x.
Add a new Digest.result_bytes convenience function.
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.
std::rt: Try stealing from all schedulers

This guarantees that if there is work to do it will be found
util: remove unused `with` function
Uncomment a test. Fixes #4449.
auto merge of #9327 : larsbergstrom/rust/tutorial_installation_tweak, r=catamorphism

I've had multiple people whom I pointed at the Rust tutorial ask me where to download the snapshot compiler, so I made the text more explicit.
auto merge of #9338 : steveklabnik/rust/rustpkg_update_manpage, r=catamorphism

I didn't update the manpage when I added the init command. Whoops.
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.