Rust bindings to libuv

This is the base-module for various levels of bindings to the libuv library.

These modules are seeing heavy work, currently, and the final API layout should not be inferred from its current form.

This base module currently contains a historical, rust-based implementation of a few libuv operations that hews closely to the patterns of the libuv C-API. It was used, mostly, to explore some implementation details and will most likely be deprecated in the near future.

The ll module contains low-level mappings for working directly with the libuv C-API.

The hl module contains a set of tools library developers can use for interacting with an active libuv loop. This modules's API is meant to be used to write high-level, rust-idiomatic abstractions for utilizes libuv's asynchronous IO facilities.