Docs: "Disk storage" in architecture needs heavy improvement

Just a note for now, will obviously require much more work.

This link: http://www.couchbase.com/docs/couchbase-manual-2.0/couchbase-introduction-architecture-diskstorage.html

Is for our "disk storage" architecture but really doesn't talk at all about the append-only disk format and all the things that come along with that (b-tree, compaction, views files, data files, etc, etc).

This is the link I would go to to find that info, so we need to rework it a bit.

Most of the discussion should go into the section about managing the interaction between RAM and disk. I would recommend a section about RAM management, a section about Disk management and a section about the interaction between the two.