nrw/observ-varhash — pull request #4 by Raynos (2014-11-28 08:37:28+00:00)
Title: Make the Tombstone `undefined`

Having a Tombstone value makes it complicated to detect deletes.

We can use `undefined` instead.

`undefined` is not JSON serializable. It's safe to use this value since `observ-varhash` should be serializable.

If someone does `varhash.put(key, undefined)` we could throw.