wip/libcouchbase 2.5.6 NetBSD

libcouchbase is a callback oriented client which makes it very easy to write high performance, thread safe programs. If you're interested in the early history of libcouchbase you might want to check out the blog post

http://trondn.blogspot.com/2011/10/libcouchbase-explore-full-features-of.html

The key component of libcouchbase is that its asynchronous, giving you full freedom in adding it to your application logic. From using the asynchronous interface you may schedule a lot of operations to be performed, and then you'll get the callbacks whenever they are performed. I do know that there are a lot of people who don't care about an async interface, so you may also enable synchronous mode. When synchronous mode is enabled you can't use this batching.