This is able to take advantage of the lower bound from the size hint.

also adds an implementation for the vector iterators

Fix compiling empty fmt! strings

accumulated doc pull requests from the queue

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

This is another big refactoring of `trans` though this is unlikely to have much of an
impact on code size or speed.

The major change here is the implementation of a `Type` struct which is the new
home for all your LLVM `TypeRef` needs. It's a simple wrapper struct, with static
methods for constructing types, then regular methods for
manipulating/interrogating them. The purpose of this is mostly to make the code
surrounding them somewhat more ideomatic. A line like: `T_ptr(T_ptr(T_i8()))` is 
now `Type::i8().ptr_to().ptr_to()`,which is much more like regular Rust code.

There are a variety of smaller changes here and there:

* Remove address spaces. At least it doesn't generate them, I haven't spent much
  time looking for related code.
* Use a macro for declaring the LLVM intrinsics, makes it look much nicer.
* Make the type for a string slice actually create a named `str_slice` type in LLVM,
  this makes reading the appropriate code much easier.
* Change the way struct and enum type names are generated. This just means
  that a struct like `struct Foo { a: int }` now produces the IR 
  `%struct.Foo = type { i64 }`, which is much easier to read. Similarly, other structs
  are a bit tighter to make it easier to read.

--- --- ---

This PR did get away from me a little, as I occasionally got distracted or as I fixed
up problems with unrelated code that were stopping me from continuing. One major
thing is that this PR contains the work from #7168, since that would have conflicted
with this and it was broken anyway. Sorry for bundling it like this.

Fixes #3670 and #7063

--- --- ---

EDIT: This no longer removes the llvm insn stats.

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.

The changes in these commits improve the IR codegen by removing unnecessary copies for certain function call arguments and stopping to allocate return values for functions returning nil. They reduce compile times by about 10% in total.

By using "void" instead of "{}" as the LLVM type for nil, we can avoid
the alloca/store/load sequence for the return value, resulting in less
and simpler IR code.

This reduces compile times by about 10%.

while cross-compiling, ar in cross toolchains are required. 
linux is not sensitive so could not see errors.

The removed test for issue #2611 is well covered by the `std::iterator`
module itself.

This adds the `count` method to `IteratorUtil` to replace `EqIter`.

replaced by the `enumerate` method from std::iterator

An Iterator implementation can be made for &const [T] if it turns out
to be necessary for some use case.

This fixes the large number of problems that prevented cross crate
methods from ever working. It also fixes a couple lingering bugs with
polymorphic default methods and cleans up some of the code paths.

Closes #4102. Closes #4103.

r? nikomatsakis

The `extra::fileinput` module landed just after 0.6 was released, and there are many
more derivable traits.

Introduce support for terminfo's subset of printf-style formatting on doxXs operations.

r? @thestinger

This fixes the large number of problems that prevented cross crate
methods from ever working. It also fixes a couple lingering bugs with
polymorphic default methods and cleans up some of the code paths.

Closes #4102. Closes #4103.