Squashed 'deps/rust-bignum/' changes from 371d543..9c44e11

9c44e11 Implement num::Integer
8681137 Merge commit '8113f8ba9d7d52e69d1513c8c4976041de49a0eb'
8113f8b Squashed 'deps/rust-gmp/' changes from 5e7542a..c4a8ff4

git-subtree-dir: deps/rust-bignum
git-subtree-split: 9c44e119ddd62470418b0877e29b3c091dc3efed
Merge commit 'aa7751dc3fa81dddd810d9c57df5a57a6b8c056e'
Updates for new rust version