Display modal window for preview of the imported data

![inspire - high-energy physics literature database](https://cloud.githubusercontent.com/assets/3083746/4151698/5230e31e-3448-11e4-8894-a7e4885fb1dd.png)
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I have a better idea than I have proposed before. Follow the comments. There are couple of points.
Here delete functions for `deleteHiddenFields()` and `setLabels()` entirely - they will not be needed.