Pluggable storage engines for carbon

Hey guys, I made a minimalist db plugin for carbon, so that it can record to other storage engines besides whisper, just as graphite-web can pull up other finders besides the StandardFinder.  It has 5 methods:

info
setAggregationMethod
create
update_many
exists

and is configured by a single config variable, DB_INIT_FUNC, which should be a visible function that yields an object fulfilling the above contract.

I've got an example plugin for Hbase at https://github.com/jbooth/graphite-data -- we could add other storage engines to that repo and I'd be happy to contribute the whole repo over to graphite-project as well.