Found issues when putting *struct{} to local cache and fetching struct{}

With the datastore, you can put with *[]*struct{} and fetch with *[]struct{}.  The local cache and memcache implementations choke on that.  So here's a fix that passes my new tests and passes all the legacy tests too.

I'm not sure if the goal of goon is to support both cases as above, but I would figure it is since the datastore does as well.