add libuv package

This adds multiple versions of libuv: "a multi-platform support library with a
focus on asynchronous I/O."

The latest 0.10.* versions are considered stable (and thus I've only included
0.10.27), while the 0.11.* versions are unstable and often break API
compatibility (and thus I've included multiple version thereof).

Versions >= 0.11.1 && <= 0.11.5 do not create shared libraries, so I've
excluded them.

This should help clean up some of our other packages that depend on libuv (e.g.
rust, nodejs) where we currently use whatever version is included in the
package's archive.