Support libuv 0.8

Change-Id: I85a6a98e7e9a96756147e2f30b14d2e325898187
Reviewed-on: http://review.couchbase.org/28622
Tested-by: Mark Nunberg <mnunberg@haskalah.org>
Reviewed-by: Brett Lawson <brett19@gmail.com>
Reviewed-by: Sergey Avseyev <sergey.avseyev@gmail.com>