Values become undefined after applying crush when object keys contain dots

When an object contains keys that include a dot (.), the values associated with those keys become undefined after applying the crush function.

_Example:_

```
const foo = {
  key1: '{
    key2: 'value'
  },
  'bar.baz': 'fiz',
};

cruch(foo)
// { 'key1.key2': 'value',  'bar.baz': undefined }
```

result should be `{ 'key1.key2': 'value',  'bar.baz': 'fiz'}`