Data as array of objects with properties which have a "dot"

Hello,
I think that there is a bug when you use data as array of object with properties which have a "dot":

```
render() {
const { tableData } = this.props;

let cols = [
{
name: '1',
label: 'ID 1'
},
{
name: '1_1',
label: 'ID 1_1'
},
{
name: '9.1',
label: 'ID 9.1'
}
];

let data = [
{
'1': 'it works',
'1_1': 'it works',
'9.1': 'it does not work'
},
{
'1': 'it works again',
'1_1': 'it works again',
'9.1': 'it does not work yet'
}
];

return (

);
}
```

To solve that I have to replace using `'9.1'.replace('.', '_')` or something similar.

Any suggestions?

| Tech | Version |
|--------------|---------|
| Material-UI | 3.9.3 |
| MUI-datatables | 2.9.0 |
| React | 16.8.6 |
| browser | Google Chrome Version 76.0.3809.132 (Official Build) (64-bit) |

No files or tests are named. Start by reproducing the provided render example with a data property named "9.1", then trace how the table resolves column names against object properties. Done means dotted property names display their values without requiring callers to rename them.

Written by the indexing model from the issue text.