work on release notes

* make the changes regarding move semantics clearer
* expand on the container work
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
auto merge of #5360 : thestinger/rust/doc, r=graydon

* make the changes regarding move semantics clearer
* expand on the container work
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