i-bem: Method getMods always returns empty hash

If we have block declaration:

``` js
BEM.decl('my-block');
```

And will create its instance:

``` js
var b = BEM.create({ block: 'my-block', mods: { a: 1, b: 2 }});
```

We can see:

``` js
console.log(b._modCache) // {a: 1, b: 2, js: "inited"}
console.log(b.getMods()); // {} — WTF?
console.log(b._modCache) // {} — WTF?
```
