[RDY] Bring neovim up to date with recent libuv changes

As of v0.11.23 (more specifically joyent/libuv@db2a9072bce129630214904be5e2eedeaafc9835) libuv's uv_timer_cb, uv_async_cb, uv_prepare_cb, uv_check_cb and uv_idle_cb no longer require a status parameter (this went unused in the first place).