Support action type without trailing slash

It would be nice to support an action type without a trailing slash. I use this for debugging purposes to manually update any part of the store, so I really only need an action type like `UPDEEP` - currently I have to use something like `UPDEEP/DEBUG`.

Start by tracing how redux-updeep handles action types and the trailing-slash convention. Verify the reducer behavior for a bare `UPDEEP` action and preserve the existing `UPDEEP/DEBUG` behavior; done means a bare action type can manually update any part of the store.

Written by the indexing model from the issue text.