onSearchChange does not provide filtered results

## Current Behavior
I have a table that I'm tracking a selected item but not the built in row selection code. I'm using the rowClick code to track which item has been clicked on and selected and using some styling to highlight the row.

I've hooked into the onSearchChange event, but I have no way to know whether the displayed results still show the item that was selected prior to filtering.

## Desired Behavior
It would be great to have some way to see what is actually displayed in the table. Ideally as part of the callback arguments.

Unless I'm missing something obvious...

| Tech | Version |
|--------------|---------|
| Material-UI | ^3.9.2 |
| MUI-datatables | 2.0.0-beta.59 |
| React | 16.6.0 |
| browser | Chrome (latest) |