syntax::diagnostics: Color the ^~~~ in green for better visibility

Fixes #7164.
Make task_rng() return @mut R instead of @@mut R
librustc: Don't allow enum struct variants to shadow structs.
Add test for duplicate definitions of structs and enum struct variants.
More 0.7 release notes
Show defaults in rustdoc usage message
fix text of tutorials
Update AUTHORS.txt
Minor doc updates to reflect #[deriving(Zero)], and small release notes adjustments.

The `extra::fileinput` module landed just after 0.6 was released, and there are many
more derivable traits.
Usable instructions for generating docs from source
Added filtered method for Option type
Methodize TypeNames
Change calls for TypeName stuff to methods
Make log_fn_time a method
Start refacting LLVM Type handling
More Type refactorings
Add the rest of the atomic operations.

This makes the handling of atomic operations more generic, which
does impose a specific naming convention for the intrinsics, but
that seems ok with me, rather than having an individual case for
each name.

It also adds the intrinsics to the the intrinsics file.
Initial Type Refactoring done
Finish up Type refactoring
Fix warnings in trans