fs: use an iterative algorithm for 'mkdir_recursive'

as requested in #6109
fs: use an iterative algorithm for 'rmdir_recursive'

For now, the windows version uses stat, just as before.
We should switch back to lstat as soon as #12795 is closed.
fs: units tests for mkdir_recusive and rmdir_recursive

The rmdir test is blocked by #12795 on windows.
Add shift and remove methods for Vec
Update last_span in replace_token
Suggest explicit lifetime parameter on some errors

Some types of error are caused by missing lifetime parameter on function
or method declaration. In such cases, this commit generates some
suggestion about what the function declaration could be. This does not
support method declaration yet.
enable mutex lowering and hardware floating point on gnueabihf. closes #10482
std::unicode: remove unused category tables
Implement lower, upper case conversion for char
Remove code duplication

Remove whitespace

Update documentation for to_uppercase, to_lowercase
collections: move hashmap's example to the struct.

Most people go straight to the struct, not looking at the module, so the
example was well hidden.
auto merge of #12849 : nick29581/rust/doubles, r=alexcrichton
auto merge of #12852 : itdaniher/rust/master, r=alexcrichton

This enables the lowering of llvm 64b intrinsics to hardware ops, resolving issues around `__kernel_cmpxchg64` on older kernels on ARM devices, and also enables use of the hardware floating point unit, resolving https://github.com/mozilla/rust/issues/10482.
auto merge of #12238 : ktt3ja/rust/lifetime-error-msg, r=nikomatsakis

For the following code snippet:

```rust
struct Foo { bar: int }
fn foo1(x: &Foo) -> &int {
    &x.bar
}
```

This PR generates the following error message:

```rust
test.rs:2:1: 4:2 note: consider using an explicit lifetime parameter as shown: fn foo1<'a>(x: &'a Foo) -> &'a int
test.rs:2 fn foo1(x: &Foo) -> &int {
test.rs:3     &x.bar
test.rs:4 }
test.rs:3:5: 3:11 error: cannot infer an appropriate lifetime for borrow expression due to conflicting requirements
test.rs:3     &x.bar
              ^~~~~~
```

Currently it does not support methods.
collections: Don't recurse in hashmap robin_hood

This switches a "tail call" to a manual loop to get around LLVM not optimizing
to a tail call.

Close #12860
auto merge of #12561 : pzol/rust/char-case, r=alexcrichton

Added common and simple case folding, i.e. mapping one to one character mapping. For more information see http://www.unicode.org/faq/casemap_charprop.html

Removed auto-generated dead code which wasn't used.
auto merge of #12573 : lbonn/rust/unrecurs, r=alexcrichton

As mentioned in #6109, ```mkdir_recursive``` doesn't really need to use recursive calls, so here is an iterative version.
The other points of the proposed overhaul (renaming and existing permissions) still need to be resolved.

I also bundled an iterative ```rmdir_recursive```, for the same reason.

Please do not hesitate to provide feedback on style as this is my first code change in rust.
std: Rename Chan/Port types and constructor

* Chan<T> => Sender<T>
* Port<T> => Receiver<T>
* Chan::new() => channel()
* constructor returns (Sender, Receiver) instead of (Receiver, Sender)
* local variables named `port` renamed to `rx`
* local variables named `chan` renamed to `tx`

Closes #11765
Refactored while_some (libstd/option.rs)

The old 'while' needed to match 2 times for each iteration. With the new
'loop' there is just one match needed.

I have also replaced 'blk' by 'f' to be more consistent with parameter
names in other functions that are implemented for Option
auto merge of #12815 : alexcrichton/rust/chan-rename, r=brson

* Chan<T> => Sender<T>
* Port<T> => Receiver<T>
* Chan::new() => channel()
* constructor returns (Sender, Receiver) instead of (Receiver, Sender)
* local variables named `port` renamed to `rx`
* local variables named `chan` renamed to `tx`

Closes #11765