Create Views 2.6 caching plugin to cache comment threads

This plugin should:

cache a single comment thread based upon the nid, the page # and hash of roles. Consider: LImit which roles we hash? (I say yes).
Instead of dirtying the cache, just compare the node updated time to the cache update time. If the node was updated more recently, re-cache. Commenting should always update the node updated time. Ensure that this is true.