Bootstrap with ImmutableUtil doesn't work

Hey,

I'm using bootstrap with ImmutableUtil like this:

```
var immutableAlt = require('alt/utils/ImmutableUtil');
alt.createStore(immutableAlt(MyStore), 'MyStore');
```

and then with bootstrap like this:

```
alt.bootstrap(
JSON.stringify(
{ 'MyStore': { data: { prop1: 'a', prop2: 'b' } } }
, null, 3)
);
```

but the returned object from `MyStore.getState()` is the store without an option to get the data object.

I've resolved it by _not_ using ImmutableUtil and overriding onDeserialize like this:

```
onDeserialize: function (data) {
return { data: Immutable.fromJS(
data
) }
}
```

Start by reproducing the interaction between ImmutableUtil, createStore, and bootstrap using the snippets in the issue. Compare the resulting MyStore.getState() with the onDeserialize workaround; done means bootstrapped state exposes the data object while retaining ImmutableUtil support.

Written by the indexing model from the issue text.