make hoodie.store.update fail when object not found

* * *

This week of work on @hoodiehq is sponsored by Cargo Media.

   Their slogan is “Small Team, Big Impact” and they are hiring
   a Frontend and Backend Dev: http://go.hood.ie/cargo-media
added hoodie.store.updateOrAdd method. Fixes #134

* * *

This week of work on @hoodiehq is sponsored by Cargo Media.

   Their slogan is “Small Team, Big Impact” and they are hiring
   a Frontend and Backend Dev: http://go.hood.ie/cargo-media
Merge pull request #135 from hoodiehq/v0.4-peanuts-store-updateOrAdd-134

V0.4 peanuts store update or add