X-Label Text Direction

### Feature Proposal

When rotating the x-labels past 90 degrees, the text direction should change so that the beginning of the label is against the axes. Instead it looks like this:

I can't find an option in the documentation to flip this text direction. Is there a workaround for this?

### Possible Implementation

`options`
```
{
scales: {
xAxes: {
textDirection: 'forward' | 'backward',
...
},
...
...
}
```