auto merge of #7161 : kballard/rust/terminfo-parm-format, r=thestinger

Introduce support for terminfo's subset of printf-style formatting on doxXs operations.

r? @thestinger
More 0.7 release notes
Show defaults in rustdoc usage message
fix text of tutorials
Update AUTHORS.txt
Minor doc updates to reflect #[deriving(Zero)], and small release notes adjustments.

The `extra::fileinput` module landed just after 0.6 was released, and there are many
more derivable traits.
Usable instructions for generating docs from source
auto merge of #7203 : msullivan/rust/default-methods, r=graydon

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
vec: remove each_const

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

replaced by the `enumerate` method from std::iterator
vec: rm old_iter implementations, except BaseIter

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`.
vec: replace `position` with `iter().position_`
replace vec::find with the IteratorUtil method
auto merge of #7263 : thestinger/rust/iterator, r=graydon
auto merge of #7200 : yichoi/rust/fix_je_mac_cross, r=brson

while cross-compiling, ar in cross toolchains are required. 
linux is not sensitive so could not see errors.
Avoid pointless allocas for "nil" return values

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%.
auto merge of #7259 : dotdash/rust/ir_improvement, r=graydon

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.
Added filtered method for Option type
std::rt: Support os::args
Remove `ast::pure_fn` and all concept of `pure` from the compiler