Update libuv to v0.11.19
Adjust build to libuv's gyp script
Backport joyent/libuv@1ad6180
Fix libuv usage

- uv_err_t and uv_last_error() have been removed
- uv_buf_t allocation has changed
- Removed logging that relied only on uv_last_error()
- Removed logging of dead conditions
- IPv4 and IPv6 have been merged
- tree.h has been made public