Prefer jQuery and Sizzle when searching for a target

`jQuery` (or `Sizzle`) offer some additional functionality. For example I am using the `:has` pseudo class that is not available when using `document.querySelector`. Therefore I think it is reasonable to ignore the performance penalty introduced by jQuery and prefer it over `document.querySelector`. 

An alternative to this would be to allow users to pass a function that returns a dom-element as a selector.