rustc: relax limits on (u)int type limit lint. Fixes #6130.
auto merge of #6561 : huonw/rust/rustc-u-int-limit-lint, r=nikomatsakis
Upgrade libuv to fix mac deadlock. #6526
auto merge of #6566 : brson/rust/libuv, r=brson

This cherry-picks a fix from upstream. It also includes another libuv patch that we were running but was accidentally removed in a submodule update.
Some cosmetic changes to num.rs
Made bytes!() accept a list of string, integer or char literals