Fix build for Rust master.
Update to compile with rust master at 4bc7672

Lots of memory corruption when running tests though.
Fix buffer allocation in `to_str_radix`

This is what was causing the memory corruption.
Import num::ToStrRadix and from_str::FromStr

Seems like they were removed from the prelude.
handle vec -> slice renaming
Update for Rust 0.11-pre (as of 2014-05-09)
Update for Rust 0.11-pre (as of 2014-05-23)
Update for Rust 0.12 pre (2014-07-28), and Cargo
Fix failure when diving zero by something
Merge pull request #5 from Dr-Emann/master

Update to newest rust, add Cargo
Add repr(C) to C structs
Merge pull request #6 from ebfe/repr_c

Add repr(C) to C structs
Add missing functions from rust-bignum
Fail when dividing by zero

Also change the order of parameters in is_multiple_of().
Also fixed indentation.
Fix division by zero failure in Mpq

It was failing when the numerator was zero, rather than the denominator.
It is recommended to ignore Cargo.lock for libraries

See https://github.com/rust-lang/cargo/issues/315.
Fix [[lib]] to [lib] deprecation warning
Fix ToStrRadix and str.to_owned() deprecations

Sadly there doesn't seem to be a replacement for ToStrRadix on user
types at the moment. See: https://github.com/rust-lang/rust/issues/18301
don't use globs for tests

This makes the tests compile again and is better style.
(It did not compile because of "conflicting types" due to the globbed
import. Unfortunately the compilers error messages are not very helpful.
Using explicit imports fixes this.)

Fixes #7.
mpz: implement `powm`