Refactor core::run to remove the ProgRepr struct, which was
a legacy from the time when destructors were implemented
using resource types.
Removed ascii functions from other modules

Replaced str::to_lowercase and str::to_uppercase
Fixed typo... And a billion other things.
auto merge of #6029 : Kimundi/rust/ascii-encoding, r=thestinger

Replaced {str, char, u8}::is_ascii
Replaced str::to_lower and str::to_upper
auto merge of #6044 : Dretch/rust/run-remove-progrepr, r=graydon

...which was a legacy from the time when destructors were implemented using resource types.
Fix incorrect replacement of `modulo` with `rem`
Move impls of `Num` out of core::num and clean up imports
Use #[cfg(not(stage0))] to exclude items from stage0

As requested on the mailing list: https://mail.mozilla.org/pipermail/rust-dev/2013-April/003713.html
Rename Natural to Integer

'Natural' normally means 'positive integer' in mathematics. It is therefore strange to implement it on signed integer types. 'Integer' is probably a better choice.
Use borrowed pointers for Integer methods

This brings them in line with the quot and rem traits, and is be better for large Integer types like BigInt and BigUint because they don't need to be copied unnecessarily.
Add Fractional, Real and RealExt traits
add a Counter iterator
Remove needless FIXME. Fixes #2811.
auto merge of #6052 : nikomatsakis/rust/remove-2811, r=catamorphism

r? whomever.
core: Comments only -- move FIXME to correct location
rustpkg: update README saying which tests pass
rustpkg: Make path searching work as described in the rustpkg doc

rustpkg now searches for package directories in ./src rather than
in . . I also added a rudimentary RUST_PATH that's currently
hard-wired to the current directory. rustpkg now uses src/, lib/,
and build/ directories as described in the manual.

Most of the existing test scenarios build now; the README file
(in a separate commit) explains which ones.
rustpkg: Correct directory structure in test scenarios
rustpkg: Preliminary work on install command

Mostly just tests (that are ignored); install command is still
stubbed out.
auto merge of #6051 : thestinger/rust/iterator, r=catamorphism,pcwalton