Parent auto check not working properly with checked and disabled children

[mariusz-jachimowicz-83]

There is mechanism to auto check parent if all children are checked https://github.com/amsik/liquor-tree/blob/master/src/lib/Node.js#L124
It doesn't work properly if any child item is checked: true and disabled: true because it makes parent item unchecked instead of checked.

refreshIndeterminateState counts checked and disabled children items and based on that it apply checked state https://github.com/amsik/liquor-tree/blob/master/src/lib/Node.js#L151 so it works if disabled items are unchecked. But disabled items might be initially checked and in that case it doesn't work properly.

Would be good to decide should disabled children be ignored or included while making parent checked because we also have checkDisabledChildren option so it might matter.