[breaking] remove `hoodie.config` from public API

`hoodie.config` has been removed from the public API
as we needed to change its behavior. `config` can now
be used internally or when within plugins. Its API
is now sync, it's using localStorage directly instead
of the `hoodie.store` API. As a side effect, the config
is now local only and does not sync anymore.

In case you you need the `hoodie.config` API back, it's
as simple as

```js
Hoodie.extend(function(hoodie, lib, utils) {
  hoodie.config = utils.config;
})
```

Place that code above the initialization of Hoodie

fixes #216

* * *

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