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.
optimized trans_to_datum::auto_borrow_obj code generation in case some trivial cases where simple copying can be applied
minor Type::opaque_trait code cleanup
will not copy trait_callee on stack if it's source expr is a plain borrowed ref
Fix broken tutorial link
Clarify that snapshots are automatically retrieved.
pacified test/run-pass/core-run-destroy on Win7x64
Fix usage for rustpkg init

When I took out the ability to make a new project by name, I forgot to
update the usage to reflect the changes.
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