updated from L to ull for easier mingw32 builds.
add the mutate_values method to the Map trait
reinstate test/bench/shootout-threadring.rs
core: Add spawn, stream and friends to prelude. #5299
add a trait for mutable iterators
hide the linkhack module in the docs
rm FIXME from use of #[doc(hidden)] on pub mod
rustdoc: Filter out private definitions. Closes #3538
auto merge of #5364 : xenocons/rust/patch-1, r=z0w0
auto merge of #5365 : thestinger/rust/map, r=catamorphism
auto merge of #5366 : tedhorst/rust/threadring, r=brson
auto merge of #5367 : brson/rust/5299, r=thestinger

r?
auto merge of #5369 : thestinger/rust/iter, r=z0w0

This can eventually be implemented on other sequence containers like `deque` (it's missing `each` too at the moment).
auto merge of #5371 : thestinger/rust/hidden, r=pcwalton
auto merge of #5375 : z0w0/rust/rustdoc-private-hide, r=thestinger
add nonempty encoding for spans

Before this change, encoding an object containing a codemap::span
using the JSON encodeng produced invalid JSON, for instance:
[{"span":,"global":false,"idents":["abc"]}]
Since the decoder for codemap::span's ignores its argument, I
conjecture that this will not damage decoding, and should improve
it for many decoders.
Test case fixup (old one tested the old bad behavior).
Update test case to conform to new restrictions on casting
add assert_eq! macro

the assert_eq! macro compares its arguments and fails if they're not
equal. It's more informative than fail_unless!, because it explicitly
writes the given and expected arguments on failure.
change some uses of fail_unless to assert_eq