Wrong css selector in _checkAncestors and _uncheckAncestors

[phillikus]

I stumbled upon this after a long time of debugging: In both _checkAncestors and _uncheckAncestors the daredveel-tree selector is missing the dot for class name selection.

li.parentsUntil('daredevel-tree') should be:
li.parentsUntil('.daredevel-tree')

like it is already in other places.

Otherwise the selector will find all dom elements (I think). If one of them is an 'li' it will be found by the filter and the first checkbox in it (in my case this was actually the first checkbox in the tree^^) will be checked / unchecked.