preliminary Linux ARM support
libcore: Add `IteratorUtil::to_vec()` method
libcore: Add `IteratorUtil::filter_map` method
libcore: Add `IteratoUtil::nth`, `first`, `last` method
libcore: Add `IteratorUtil::fold`, `count`
libcore: Add `AdditiveIterator`, `MultiplicativeIterator`, `OrdIterator`
libcore: Add `IteratorUtil::all`, `any` method
Correct the example given for a future, add punctuation where necessary
Add a small section on futures to the tutorial
auto merge of #6249 : crabtw/rust/arm, r=brson

It uses the private field of TCB head to store stack limit. I tested on my Raspberry PI. A simple hello world program ran without any problem. However, for a more complex program, it segfaulted as #6231.
auto merge of #6560 : gifnksm/rust/iterator-utils, r=thestinger

This pull request adds following methods and traits.
```rust
pub trait IteratorUtil {
(snip)
    fn filter_map<'r,  B>(self, f: &'r fn(A) -> Option<B>) -> FilterMapIterator<'r, A, B, Self>;
(snip)
    fn to_vec(self) -> ~[A];
    fn nth(&mut self, n: uint) -> A;
    fn first(&mut self) -> A;
    fn last(&mut self) -> A;
    fn fold<B>(&mut self, start: B, f: &fn(B, A) -> B) -> B;
    fn count(&mut self) -> uint;
    fn all(&mut self, f: &fn(&A) -> bool) -> bool;
    fn any(&mut self, f: &fn(&A) -> bool) -> bool;
}

pub trait AdditiveIterator<A> {
    fn sum(&mut self) -> A;
}

pub trait MultiplicativeIterator<A> {
    fn product(&mut self) -> A;
}

pub trait OrdIterator<A> {
    fn max(&mut self) -> Option<A>;
    fn min(&mut self) -> Option<A>;
}
```
rustc: Cleaning up bad copies and other XXXes
auto merge of #6582 : catamorphism/rust/cleanup, r=catamorphism
Use cond! macro where appropriate
Use pattern-matching instead of conditionals where appropriate to improve code clarity
Convert various inner doc-comments to outer doc-comments
Use four-space indentation, add trailing commas, and remove unnecessary uses of the return keyword
auto merge of #6586 : bjz/rust/formatting-and-conditionals, r=thestinger
iterator: remove `first`

it's the same as `next.unwrap()`, but there's no way to check the
length of an iterator so this isn't a good pattern
iterator: make nth and last return Option

There isn't a way to take the length of any iterator, so failing on a
zero length would make these much less useful.