Should we call mixins always in life-cycle hooks

[mitar]

Currently, we are calling them from the life-cycle methods, allowing user to do things before, after, or event not call super. But if they forget to call super, mixins are not called. The question is if we really want to allow not calling them. Or do this customization of allowing to do things before or after is even a good one.

We could just have it so that mixins are always called, and then methods are called, which are empty by default.

(Same for DOM changes hooks?)

Order could match the same order of calling events. See #4. But while for events we have to decide when to call them because of unclear way how to offer customization. Leaving mixins calling in methods could allow such customization. But it can introduce also silent errors.