New Feature: axisLabel.autoRotate

### What problem does this feature solve?
If the axis labels do not fit, then autoRotate will automatically calculate axisLabel.rotate to make them fit.

`axisLabel.interval='auto'` will cause missing/skipped labels, like this:

`axisLabel.interval=0` will cause collision, like this:

In my opinion, autoRotate will go from 0 to 45 to 90 degrees, depending on the fit, like this:

### What does the proposed API look like?
```
axisLabel.rotate = () => {
if(this.doesNotFit && this.autoRotate) {
this.rotate = calcRotateDegrees();
}
...
}

```