api3: Implement HTTP functionality

This is still a bit rough around the edges as HTTP really goes through a
whole different code path

Change-Id: I8c783cc2bfcf7b7faf856673f51a79064aa4583d
Reviewed-on: http://review.couchbase.org/39145
Tested-by: Mark Nunberg <mnunberg@haskalah.org>
Reviewed-by: Brett Lawson <brett19@gmail.com>